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The great dam on the Tiber

In 1983 a large number of poles came to light in the Tiber and were photographed by Renato Codovini. From the investigations of Mario, Marco and Matteo Tosti, it has been hypothesized that they formed the basis of the dam, born in the 12th century, up to 6 meters high, which enclosed the Fratta fortress in a basin. From a document of 1527, in fact,  we have news of an artificial basin  upstream of the bridge over the Tiber whose waters could form a "very clear lake", as it was described in 1565 by Piccolpasso. We leave the floor to the study of the engineers Mario, Marco and Matteo Tosti who have kindly allowed to report on this page.


Study published in “L'Ingegnere Umbro” n. 43, December 2002 and reported to us by Alvaro Gragnoli. Photos added by Fabio Mariotti.

(edited by Di Mario, Marco and Matteo Tosti)

The discovery of a foundation piling.

Dredging works on the Tiber bed in 1983 brought to light a large number of piles about 80 meters downstream of the bridge. It was Renato Codovini, unrivaled researcher of local history who noticed them, photographed them and understood their importance as the remains of the foundation of an ancient lock. A few years later, in their valuable thesis ("Discovery of the dam on the Tiber river, Umbertide in the province of Perugia", University of Florence, academic year 1987/1988), Alberto Crocioni and Roberto Codovini extensively documented the structure and the construction technique of the work, characterized by an original checkerboard foundation in oak planks and river stones.


We wanted to deepen the subject, trying to bring engineering to the aid of history, intrigued by the imposing foundation piling in the direction of the river current, for an estimated length of at least 15 m: this clue suggested a huge investment, both financial and technical-organizational and, therefore, a purpose of great strategic importance. We tried to imagine what the clients intended, which could not only be to operate the blades of the nearby mill, which could have been built elsewhere with a much more modest barrier, perhaps on a small tributary of the Tiber. The most plausible and fascinating hypothesis was that the dam served to create a reservoir so large that it permanently flooded the moat all around the city walls; perhaps Cipriano Piccolpasso had not exaggerated in 1565 in using a superlative - “very clear lake” - at the sight of the Fratta river, which he described and represented in the oldest panorama of the place.

And this is precisely the thesis we intend to demonstrate, reconstructing the history of the "great dam" and its structural and functional configuration.

Archive news

There is no direct and detailed information on this work, about which all the writers of local history have been silent. Only the military engineer Piccolpasso, in the aforementioned drawing, traced the structure of the dam, albeit with barely hinted lines, perhaps because at that time it had already lost its importance from a military point of view, which represented the topic of main interest for the author: commendable example of a good engineer who does not waste even an unnecessary pencil stroke. Or a sign of low satisfaction for the reimbursement of expenses requested in the parcel: "30 bajocchi for the horse from Castello alla Fratta, 30 bajocchi for dinner and dinner at Fratta, 10 bajocchi for those who will help me to measure, 30 bajocchi for the horse for Perugia ; and more 50 bajocchi made to give to the femeglia de messer Paulo, called messer Gherardo soldier of fortress for the fatigas of said messer Paolo ”. The surrounding tour of these last 50 bajocchi - delivered to a soldier to give to the family of Mr. Paolo who had struggled - arouses some suspicion, dear engineer Cipriano!

Instead, there is indirect information on the existence of the barrier, the oldest of which dates back to a registration dated February 6, 1527, where the expression versus clusam molendini is used, in describing the activities carried out in the buildings adjacent to the barrier, at edge of the river, at the end of Piazza S. Francesco. In fact, in that area the dam made it possible to supply the necessary energy to various factories: the water, conveyed along a derivation canal, through the opening of the respective doors according to agreed shifts, operated the millstone of the Molino di Sant ' Erasmus; he made the wheels of the blacksmiths turn for the grinding of sickles and other irons (swords, spears…); he operated the wooden mallets in the fulling machine, to compress and firm the woolen cloth; it flowed into the public wash basin; finally it returned to the riverbed of the Tiber downstream of the dam.

The lack of other more detailed information has prompted us to seek objective elements to find out more.


Photo by Fabio Mariotti.

La grande diga sul Tevere

The simulation of the reservoir

First of all, an attempt was made to estimate the extent of the reservoir.

In a first phase, the configuration that would have today, in the event of restoration of the dam, was identified after evaluating the height of the dam: for this reason, the level of the floor of the ancient public washhouse of Caminella was taken as a fundamental reference, where in the 1960s the original tank was still visible, even if its use had been converted into a breeding leech for the pharmacy, using the stagnant surface water that was collected there. This reference is certain, as the share has remained unchanged with respect to the period of use; on the other hand, the presence - in the immediate vicinity and at the same level, of the other users of the dam just described, much more relevant - excludes the hypothesis that the wash house, with the abundance of the reservoir, used vein water.

The height of the floor of the public wash house, which was equal to 238.25 m asl, can therefore be reasonably assumed as the overflow level of the reservoir, the contours of which have been defined on the basis of the corresponding level curve in the current configuration of the land.

The boundaries as determined above were subsequently corrected on the basis of changes made by man and the river over the centuries, of which traces have remained.

These elements reasonably lead to the conclusion that, in the period of maximum military efficiency of Fratta Perugina (15th century), the reservoir surrounded the entire islet of the historic center, which could only be accessed through the rampant bridge of the Piaggiala, the drawbridge. della Rocca and the bridge over the Tiber.


The height of the barrage

The difference between the overflow level at 238 m asl deduced above and the altitude (232 m asl) of the river bed area from which the foundation piles emerge today, allows us to estimate the height of the dam at about six meters: for those times the great Fratta dam was truly a gigantic work.

Site plan in a drawing by the authors


(1)  Public wash house; 

(2)  Molino di Sant'Erasmo; 

(3)  Churches of Santa Croce, San Francesco and San Bernardino; 

(4)  Great dam; 

(5)  Tiber; 

(6)  Bridge over the Tiber; 

(7) Regghia stream; 

(8) Rocca, with drawbridge and “calzo de fuora”; 

(9)  The rampant bridge of the Piaggiola, the round tower and the Porta della Campana.



The functions of the barrage

The significant complexity of the project, the grandeur of the structure and the economic burden of its construction confirm the thesis of a military use of the large dam: its primary utility was to keep the moat around the walls constantly flooded, for safety. of the inhabitants of the castle, and to reduce the stresses on the foundation pillars of the bridge just upstream. The other benefits of an economic nature (supply of energy for production activities and taking fish from the weir), although more important for the well-being of the population, were collateral and irrelevant to the decision to build the work.

The birth

The non-existence of records relating to these works does not allow us to establish with certainty the period to which they date back. However, the hypothesis is likely that only after the passage to the dominion of Perugina (1189) did the conditions exist to build such an imposing work.

Only a city like Perugia could have had the necessary economic capacity, technical-military knowledge and political motivations: this is precisely the period in which it pursued a strengthening as a Municipality, to consolidate its vital space among the great powers of the moment in the Center- Italy, capitalizing on the advantage of equidistance from Florence and Rome.

On the contrary, in previous times there were no conditions to justify such a huge effort: at first - until the death of Matilde di Canossa - it was marginality, as a remote border place of the Marquisate of Tuscany, to discourage the investment. Then after the dismemberment of this in many territories dominated by small lords, it was the scarcity of economic resources that made the enterprise impracticable.

The same lack of news relating to the construction of the dam, attributable to the disappearance of the Annals of Perugia - from 1190 to 1230 - relating precisely to the presumable period of construction, constitutes a confirmation clue of the thesis that is being supported, as it is not likely that such an impressive work no formal acts have been performed.

It can be concluded by affirming that the construction of the great dam can be placed between 1189 (beginning of the dominion of Perugia over Fratta) and 1230 (availability of the Perugian Annals).

The overall design system

Let us now try to define other details of the dam and its functional organization.

The reservoir was divided by a "central guardian", slightly inclined with respect to the flow direction of the river. Between this and the left bank - the western basin - the main current had to flow, which flowed downstream from the top of the dam perpendicular to the bank.

The other segment, arranged obliquely so as to extend the length of the front of the jump, was perhaps of a higher height so as to contain the damage on the left bank, of great value for the presence of production activities: the mill, the blacksmiths, the fulling machine; in short, a kind of industrial area of the lower village.

The capacity of the reservoir, considering the height of the dam equal to 6 m, the width 70 m and the length of the lake upstream of 1,200 m, was estimated at 250,000 m³.

The maximum power obtainable, with a useful flow of the river assumed equal to 10 m ³ / s, has been estimated at 600 Kw, based on the following relationship:     P = p Q g Δ H

P = power; 

p  = water density; 

Q = volumetric flow rate; 

Δ H = geodetic difference in height  

Assuming a width of the adduction channel to the mill equal to 1 m², a current speed of 2 m / s, a head of 3 m and a reasonable efficiency for those times, the order of magnitude of the useful power can be placed around 100 Kw.

For a correct functionality of the military security system, precautions were also taken to prevent the ditch being buried due to the debris deposited by the floods of the Regghia, at the point where it flowed into the reservoir under the Rocca, slowing down its fury. We think that this was precisely the function of the “ … lock of the river of the Regghia alter dicta el Battifosso which is contiguous to the horto della Roccha and to the walls of the said castle… ”.

The death

Let us now try to clarify how and when the barrier ceased its function.

In this regard it is known that on 20 October 1610 two arches of the bridge and the Mulinaccio tower collapsed at the corner of the walls along the river; the contemporaneity of the collapses, just upstream of the great dam, made us suspect that the disaster had originated - with a "domino effect" - from the deterioration of the dam. Archival records confirmed the hypothesis: as early as 1606, in fact, the barrage had shown the urgency of repairs.

The question became the subject of a legal dispute on the occasion of another flood, in 1611; the tenant complained that the mill was " spotless and unsuccessful " and the dam had been " badly kept and badly restored ". The subjects called into question - the Bishopric of Gubbio and the Community of Fratta - tried to discharge each other the responsibility and the burden of reparation; the first claimed that the dam had been damaged by the collapse of the bridge; the second claimed the opposite thesis, attributing the expenses to the Bishop, as in fact " it had always been ". It seems to us that - Monsignor forgive us! - the Community was right, as it is really strange that the very heavy debris of the bridge, instead of lying on the bottom of the river, overwhelmed the barrier a hundred meters downstream.

However, for our deductions, it is only interesting that the mill did not grind since that time, demonstrating that the dam had just collapsed. But there are many other confirmations: even the blacksmiths were forced to go to other mills in the vicinity that had suitable wheels; but the loss of those of Sant'Erasmo was incurable if, a few decades later (1647), four blacksmiths from Fratta brought 14,000 raw sickles to Rome (hammers were not yet produced in the red Umbria), entrusting the finishing to grinders of the capital . Therefore, even the wheels had finally stopped. Similarly, the activity of the fulling mill was moved to a similar factory, in Pian d'Assino, whose structure is still visible on the left bank of this stream, just upstream of the bridge that crosses it just before flowing into the Tiber.

All these facts concur to confirm the dependence of the factories in Piazza San Francesco on the large barrage and the superimposition of their respective periods of operation (from about 1200 to 1611). In short, the dam was born when it was necessary to protect the safety of the castle with a lake and no one wanted to take care of its maintenance since these needs were overcome by the evolution of warfare. For all the time in which it was of military interest - and only for that - it was also a source of work and well-being, respecting a sad priority to which man has always had to submit.

The death sentence of the Great Dam was issued for the opposite reason that led to its conception.

Here below some photos  with Mario Tosti and the Tiber river south of the bridge in the place of the "great dam"; photo compared with the 1565 drawing by Piccolpasso showing the position of the dam. Picture of  by Fabio Mariotti.


-  " The Great Dam of Fratta Perugia ", by Mario Tosti, Marco Tosti and Matteo Tosti, in  The Umbrian Engineer ” n. 43, December 2002

- Photos and original article drawings: Renato and Roberto Codovini, Mario, Marco and Matteo Tosti.

- Photos added: Fabio Mariotti


by Mario Tosti

(taken from "Pagine Altotiberine" *, n. 45, 2011)

* "Pagine Altotiberine" is a series of books published by the historical association Alta Valle del Tevere, which gathers members from our valley.

The main objective of the Association is to provide citizens with the possibility of publishing texts on local history, without any charge for the author, who receives five copies of the book that contains his work free of charge.

The association is financed by the members' fees, who receive the three books that are published every year for free.


















The history of the construction

The history of the Collegiate Church has been the subject of research that has made it possible to know the events in an exhaustive way. In the first place, they were deepened in the monographic book by Monsignor Pietro Vispi (1) , from which we extracted a summary of the information regarding the origins and construction details of the church. We also submitted to Monsignor Pietro, who kindly made himself available, the thesis supported in these notes, to exclude that any additional information to his knowledge would dismantle some links in the logic of the deductions.

The chronicles of the time tell that, on 14 September 1556,

"A girl of 7 years old ... who was struppia [crippled] in a cossa [thigh], so that she could not walk without support, while she was praying in front of this image [Editor's note: the Majesty painted in a small chapel near the Collegiate building ], it is said that this spoke to him and incontinent found herself free and healthy, and walked frankly ".

A few days later the bishop of Gubbio sent his vicar Cesare Sperelli, who

"... visitevit ecclesiolam beate et gloriosa virginis marie vulgo called the madonna della regghia prope et juxta muros castri fratte ..."

Therefore: the small church in which a miracle took place stood near the walls of Fratta, in the word "Madonna d ella Regghia".

Out of thanks, it was decided to build a temple in the immediate vicinity.

From the deed of sale of the land of 15 April 1559 we learn that the owners, Graziani of Perugia,

"Give and concede for the Madona and the chapel in writing to the Comonità della Fratta all the reasons that they have above the Capella or true Oratory of the Madona de la regghia in front of the walls of said Castle and also above the houses in the said adjacent Chapel and such a quantity of land contiguous to the said chapel that it will be necessary for the construction of a church to be built in that place in Honore de Dio and Della Glorioss. Virgine Maria provided it does not exceed the containment of the garden contiguous to said Capella ... ".

So: the church was surrounded by a group of houses and a vegetable garden.

Shortly after, thanks to the copious alms of the people, the construction works of the temple began, with the contribution of various architects: Galeazzo Alessi, Giulio Danti, Bino Sizi, Mariotto da Cortona.

A drawing by Piccolpasso shows that in 1565 the construction of La Madona had reached its first register and leads us to believe that the houses adjoining the chapel with the miraculous image, designed to the west of the church, towards the Regghia, were in the area of the current Reggiani palace.

The Collegiate was completed in 1597-1599.

After about twenty years, in 1619, the original dome showed a lesion: consequently it fell or, more likely, was demolished. Today you can get an idea of the primitive dome from the painting by Bernardino Magi kept in the church of San Bernardino. The reconstruction of the current dome, no longer with a lowered sixth but with a round sixth, with a smaller base diameter, was entrusted to Filippo Fracassini (until 1650) with the architects Rutilio, first, and Beniamino Sermigni, later. In order to consolidate the base of the vault, without compromising

“The ornamentation of the interior ... the order of the beautiful columns, to whose transport is to be attributed

one hundred and forty-one pairs of oxen were needed in 1623 ”.

The lantern on top of the dome was finished in 1664, along with the wooden doors.


The clues to the solution of the riddle

The above information tells us everything about the reason for the location of the Collegiate Church, about the artists who built it, about its main events; but they do not reveal the reason why the church of the Patrona has been set up in the configuration from which, for over four centuries, it has scrutinized the life of the mortals who alternate around its bulk from the top of the lantern.

By asking ourselves this question during a walk with friends around the octagonal church, the intuition emerged that the orientation had been chosen with the intention of offering the best scenery to the faithful who proceeded to the temple. The research that followed led to the emergence of several elements that seem to support this hypothesis, as we will try to demonstrate in the following pages.

Starting from the assumption that the orientation of the church could not have been accidental, let us analyze the objective elements of knowledge currently available, from which a reasonable answer to the enigma can be deduced. For this we make constant reference to figure 1, where the essential elements of the church plan and the nearby buildings indicated by historical sources are shown.


1. "In the Italy of the fifteenth and early sixteenth centuries ... the formation of sanctuaries on places of miraculous events attributed to the Madonna ... There was also the trend, made known by the solution of the Sanctuary of Loreto (started in 1469 ), to incorporate the pre-existing chapel inside. " (2)

2. The small church outside the walls of Fratta with the miraculous image was adjacent to some buildings, as evidenced in the historical summary reported above. Therefore there were not even the practical conditions to incorporate it, unless the adjacent buildings were demolished.
















3. "The attention to the astronomical orientation of places of worship, carefully researched in the Middle Ages, disappears in Renaissance buildings when the introduction of the compass and modern philosophical and scientific theories loosened the bonds of a mythical, magical, mysticism that united the men of the Middle Ages with the observation of the sky, favoring instead the positioning of the building in relation to the urban context.


In the case of the Collegiate Church, some measurements were nevertheless carried out to verify the actual orientation of the building with respect to the astronomical cardinal points and to identify any related explanations. The results of the surveys, shown in figure 2, allow us to deduce some considerations.























The eight-pointed decoration visible on the floor in the center of the church, similar in shape to the wind rose, is not related to the cardinal points, but is only a decorative element subordinated to the shape of the building, which in some way reflects.

The particular historical methods of foundation of the octagonal buildings were also verified: " Generally the orientation of the octagon required that the cardinal directions pass through the vertices of the polygon, a rule that was not always respected during the construction of the baptisteries while it was respected, in the period around 1000, when several octagonal churches were built. " (3)

In our case, the orientation of the octagon does not respect the criterion of cardinal points passing through two opposite edges.

It would seem to be possible to say that the altar is oriented at the dawn of the winter solstice, with the sun rising behind the celebrant, but there are no openings in the wall that capture and highlight this phenomenon which, consequently, does not seem to have been priority in the plant of the building.

In conclusion, it seems unlikely to attribute an astronomical explanation to the orientation of the church. " (4)

4. The sandstone portal to the north, consisting of two columns surmounted by a tympanum, projects perpendicularly to the wall face. Above the tympanum there is a round arch of unloading (platband), made of bricks in a radial arrangement, which is used above the architraves in order to reduce or eliminate the bending stress.

5. The west portal, apparently the twin of the north one, has several peculiarities: it protrudes from the wall facing in an oblique direction, with an angle of about 24 ° with respect to the perpendicular to the wall; the brick arch above the tympanum is not visible on the outside.

6. A panoramic drawing of Fratta (figure 3 shows the detail of the area in question), made in 1565 by the military engineer Cipriano Piccolpasso, does not seem to show the opening to the west of the Collegiate, although the church appears to have been erected until the first register: the signs on the left of the wall are not in the center of the side of the polygon and do not have a regular geometric shape, but seem similar to trees, such as those shown also on the right of the building. It should be noted that the design is to be considered very reliable, as evidenced by the accuracy of the details represented in the other more important buildings.
















The drawing highlights another important detail: the original path of the Regghia is moved, compared to today, towards the Rocca, confirming the subsequent movement of the river bed and, therefore, the need to build a new bridge, as documented in point 9 following.

7. The differences between the two portals exposed in the three previous points reasonably suggest that the one to the west was opened at a later time, after the construction of the first register. In any case, the anomaly highlighted in the west portal suggests that this had been considered in the alternative to the north one: therefore the importance of the latter must have been truly extraordinary if it had prevailed, for the purposes of choosing the orientation, with respect to to the alternative of enhancing the chapel which had even motivated the work.

8. At the time of the design of the church, the oldest and most important access inside the walls was undoubtedly that of the Porta della Campana, which showed the emblem of the castle (the ancient lily in bas-relief, an ancient weapon of Florentines (5 ) ) and allowed the people to enter the main road network of the valley: the "Strada del Piano", which connected Città di Castello to Perugia, along the left bank of the Tiber, across the bridge over the Carpina, the church of Santa Maria, the Collegiata (in fact), the Madonna del Moro and Ponte Felcino. Therefore, for the inhabitants of the castle of Fratta, the most important way to go to the Collegiata was the one leaving the Porta della Campana, which entered the “Strada del Piano” through the Piaggiola and Boccajolo. It was also the shortest way, because the possible alternative was to go down the Via Retta (the Corso), leave the walls towards Piazza San Francesco and go up to the Collegiate Church on Via Soli.

So: for the people of the castle of Fratta it was natural to access the large church outside the walls from the "Strada del Piano".

9. There is news (6) of an old bridge over the Regghia starting from July 1632, from which it is deduced that it was probably composed of masonry heads where wooden beams rested for crossing. The continuous adjustments and renovations in the seventeenth century indicate how much it was subjected to wear. In particular, he had had to work overtime in absorbing the transit of heavy loads of materials coming from the furnaces of the Borgo Superiore, necessary precisely for the "factory" of the church of the Madonna della Regghia. Other consolidation works were carried out in 1726. Furthermore, the state of the bridge was a source of dangers, so the situation became increasingly unsustainable.

Finally, in the meeting of April 4, 1770, the City Council took the question head-on:

"Being that since some years ... several times thought by the Defenders and by the representatives of this Earth to obviate the dangers that have occurred and that can happen in the future in passing with horses slaughters and some over the bridge that passes over the river Palace under the church of the Most Holy Virgin, which being so narrow and without sides or parapet, it happened several times that horses and oxen were in danger of rushing with loads and wagons, and other hauls. "

By cutting off the bull's head, it was decided to redo the now unsafe bridge from scratch, making it wider, with sturdy sides and suitable for bearing greater loads.

In confirmation of this intention, the Chapter of the Collegiate gave the Municipality "land for the construction of the new bridge over the Royal Palace in the direction of Montone" (7) . The project was promptly carried out, if in the rough color plan of 1780 by Giuseppe Fabretti (8)  (figure 4) the bridge is located in the new position and is connected through a twisted junction to the old route of the “Strada del piano”, which in the meantime had become less and less important, compared to the more recent road on the right bank of the Tiber. The road will only subsequently be rectified and enlarged, forming the current Via Veneto.

















The construction of the new bridge in a location other than the original one was also determined by the need to expand the square under the Rocca (9) , whose first modest works began in 1803, in order to solve a very old problem. At the end of 1846 the Judiciary of Fratta bought, for this purpose, another piece of land with these reasons:

"... the need for this expansion [Editor's note: of the area for the livestock market] is making itself felt every more and openly demonstrated by the last Cattle Fair in which not only the current square was filled with oxen, but even though the adjoining road that leads to the house of Signor Mavarelli and a large part of the Collegiate field that would be occupied by the proposed extension ... ".


It is reasonable to think that on that occasion it was decided to move the riverbed of the Regghia away from the tower.

The refurbishment of the area was completed in 1880, with the construction of the retaining walls and the raising of the level of the market square. Ernesto Freguglia had just had time to paint the area (1875) in its original configuration, with the clearing still at the level of the bed along the river bank.

In this year 2011, a suggestive realization has turned back the hands of time, restoring a condition similar to that of the seventeenth century, demonstrating how man does not disdain to emulate Penelope in adapting the environment to his variable needs.


A hypothesis for solving the riddle

On the basis of the objective information detailed above, it can be deduced that the configuration of the area of the Collegiate and the surrounding area in the year 1600 (immediately following the completion of the church) was that shown in figure 5, which can be compared with that of figure 6 , relating to the year 2000.

For a more immediate perception of the changes undergone over the last four centuries, the situations indicated in the plans are replicated in the drawings of figure 7 - taking advantage of the prodigious pencil of Adriano Bottaccioli, used to photographing scenarios that have now disappeared from our castle - and in figure 8 , in which the changes that led to the current scenario are superimposed.




























































At this point we can deduce a likely explanation for the enigma posed to us, which we set out below.

Already in the positioning phase of the new church, it was decided not to incorporate the small chapel with the image of the Virgin, as was customary in that period (point 1), because it was too close to other valuable buildings existing nearby ( point 2).

The church was originally conceived with the main entrance - and, initially, probably the only one - corresponding to the current north portal, aligned with the main access road from the castle, as shown in the drawing in figure 7. In this way the scenography that was presented to the faithful on their way to the church (point 8) was of the utmost spectacular.

On this portal, at the same time as the construction of the wall, the discharge arch was created above the opening (point 4).

It is probable that only later, during the construction of the church, did someone come up with the idea of "uniting" the old chapel and the large church in some way. The goal was achieved with the opening of a second access (not drawn in the overview of the Piccolpasso referred to in point 6) on the side facing the original aedicule, which was obtained by tearing apart the masonry. On the occasion, the platband was not built on the external face, for various possible reasons: either because the engineers were less scrupulous; or because it was more complicated to obtain an aesthetically acceptable result, having to inscribe the arch on an opening obtained by tearing. However, it cannot be excluded that the platband was built at a lower level, so as to be hidden by the sandstone tympanum. Jutting out from the wall, a twin portal to the existing one was built, but with an anomalous angle, in order to orient it towards the original chapel (point 5); in fact the land donated for the construction of the church was in fact "contiguous" to the chapel, as reported in the deed of sale of the land of 1559.

The anomalous angle can have two different explanations, depending on whether the construction of the portal was started after or before having decided to demolish the chapel - perhaps due to the precarious state, such as not to justify its restoration - and to move the image of the Virgin inside the church.

In the first case, in anticipation of the maintenance of the chapel, the new portal should perhaps have constituted one of the two ends of a portico connecting the new and old structure; faced with the decision to move the effigy and demolish the aedicule, the portico was no longer built, leaving the work unfinished, due to the unexpected disappearance of the final destination.

In the hypothesis that the architects of the work were less fickle in their decisions, it seems more likely that the idea of building the anomalous portal was triggered after having decided to demolish the chapel, with the consequent necessary compensation by evoking it forever. in the imagination of the faithful.

In any case, in all probability this architectural strangeness remains today to indicate the direction along which the ancient chapel with the Majesty must have been.

The opening of the second portal will have involved the need to move the altar, placing it on the side of the octagon opposite the one between the two doors, in order to give a new symmetry to the temple.



If the one described was really the sequence of decisions and works, the enigma we tried to unravel was born, many decades after the completion of the Collegiate, following the decision to move the route of the "Strada del piano" and to replace the old bridge over the Regghia on the road to the upper Borgo with a new one, in a different position.

There were two reasons:

  • the state of decay and danger of the bridge;

  • the need to expand the space around the fortress to be used for the livestock market, after having moved the riverbed of the Regghia and demolished the access ramp to the now obsolete drawbridge.

Basically: the orientation of the temple and the presumed location of the original main access road to the church explain each other; with the modification introduced since, during the 18th century, the pre-existing bridge and road were moved to the north-east, the original scenography was canceled, creating the enigma for which this hypothesis of solution was proposed.



In the recent restructuring of the area surrounding the Rocca, the opportunity was lost to restore the original scenography to the Collegiata, with the simple positioning of the new sidewalk along the route of the ancient Strada del Piano.


* * *


Thanks to Alvaro Gragnoli who, thanks to his intuition, started the research and to those who made their knowledge available: Giovanni Cangi, humanist engineer, as regards the engineering aspect; Francesco Rosi, architect, expert and passionate about archaeoastronomy; Monsignor Pietro Vispi, parish priest of the Collegiate, precious source of historical information, Adriano Bottaccioli, art director of communication and painter.



1. PIETRO VISPI, The Collegiate Church of Santa Maria della Reggia, Radio Elettra & M SpA School, Città di Castello, 2001

2. LUCA SPORTELLINI, “The Sanctuary of Maria Santissima Assunta in Rasina”, Fabrizio Fabbri Editore, 2011, p. 24

3. A. GASPANI, Astronomy and geometry in the ancient Alpine churches, Priuli and Verlucca editori, 2000, Turin

4. Contribution by FRANCESCO ROSI

5. BELFORTI - MARIOTTI, History of Fratta, year 1780

6. CODOVINI - SCIURPA, Umbertide in the XVIII century, GESP, Città di Castello, 2003, p. 42

7. PIETRO VISPI, The Collegiate Church of Santa Maria della Reggia, Umbertide, 2001, note on p. 60

8. GIUSEPPE FABRETTI, News of the Land of Fratta, (ms BAP 2011)

9. RENATO CODOVINI - ROBERTO SCIURPA, Umbertide in the 19th century, 2001, GESP, Città di Castello, pp. 51, 122, 377.

Fig. 1 Cattura pianta con cappellina.jpg
Fig. 2 Cattura Orientamento.jpg
Fig. 3 Cattura Piccolpasso.jpg
Fig. 4 Cattura Fabretti.jpg
Fig. 5 e 6 Cattura Pianta 1600 e 2000.jpg
Fig. 7 Cattura Disegno Adriano 1600.jpg
Fig. 8 Cattura Disegno Adriano 2000.jpg
L'Enigma della Collegiata

by Mario Tosti


In the memory of Renato Codovini and Amedeo Massetti






















With the following notes I propose to shed light on the events of a sundial found in our historic center. I try to demonstrate the hypothesis that it represented the local reference for solar time: the time of Fratta, our local Greenwich mean time.

For this mission, she lived in symbiosis with the clock of the Torre della Campana, which stood on top of the Piaggiola. His odyssey began on a window sill in front of the Rocca, on the first floor of the building that housed the headquarters of the Podestà and the hall of the municipal council, in Via Alberti. After a couple of centuries of honorable work, she was evicted and imprisoned under the plaster of the Garibaldi's room in Piazza Fortebraccio. Today he is enjoying his well-deserved retirement in the bucolic Umbrian countryside.

For the sake of completeness, I have also tried to reconstruct the evolution of time measurement tools available to the community up to the present day.

Let us hope that they continue to measure a time of peace and serenity.



Around the middle of the twentieth century, in the course of renovations, a sundial was found under the plaster of the wall in front of the entrance to the room on the ground floor of the building at no. 9 of the current Fortebraccio square, in front of the Rocca (Figure 1). It was Rinaldo Giannelli, owner of the restaurant, who reported it to me, proposing to look for clues about the story.






At first, I had come to a hypothesis that turned out to be incorrect after meeting Mauro Bifani who, together with Manlio Suvieri, was carrying out a research on the sundials of Umbria. I pointed out to him the existence of our find, which has become the subject of his expert analysis. In the book they subsequently published - The ancient hours, Sundials and Roman-style clocks in the municipalities of Umbria, Futura edizioni, 2017 - an entire chapter was dedicated to The sundial of Piazza Grande alla Fratta, in which I was able to integrate with my historical reconstruction of the results of their technical and functional research.


The small sundial (36 cm x 36 cm) of Fratta, in octagonal terracotta, at Italic hours, was designed to be used in a horizontal position.

Several engravings are visible on its surface.

  • At the top, the date of construction (1658) is engraved.

  • A little below, a motto in Greek and another in Latin are engraved:                                                             “ΧΡΟΝΟΧ ΑΝΤΑΧΟ Υ ΑΝΕΜΕΙ” (Time resists winds).                                                          “AMBIGUIS ALIX LABILIS HORA VOLAT” (The fleeting hour flies on mysterious wings).                                            In agreement with the authors of the book, I add a different translation reported by Mons. Pietro Vispi, also based on the identification of a Greek "p" partially canceled by a crack in the tile:                                           "ΧΡΟΝΟΣ (Π) ΑΝΤΑΚΟΥ ΔΙΕΠΕΙ" (Time always arranges everything)                                                   “ΑΜΒΙGUIS ALIS LABILIS HORA VOLAT” (Time that passes flies with elusive wings).                                        I gladly report the two translations, both fascinating, also to demonstrate the complexity in the interpretation of the thoughts handed down to us from the past.

  • The inscription “AD ALTITUD GRAD 43” confirms that it was built for our latitude.

  • The symbols of the four main zodiac signs are represented: Cancer, Capricorn, Aries and Libra.

  • The names of the winds are engraved on the external frame: Mezzodì, Garbino (term used on the Adriatic coast to indicate the Libeccio wind), Ponente, Maestro, Tramontana, Greco, Levante, Scirocco.



Hypotheses on the events of the sundial can be deduced starting from the information concerning the measurement of time in the castle of Fratta and the function of the existing buildings in the area of the discovery (Piazza Fortebraccio, Via Alberti, Piaggiola).

A recording dated 1477 refers to a Porta della Campana (figure 2), open towards Montone in the north corner of the castle walls, at the top of the Piaggiola. Originally, a tower 22 meters high rose above the gate. In the 16th century it was raised with a wooden tower of 11 m, at the base of which a niche was obtained, with the painted image of the Madonna. At the top a small loggia was opened to house the public bell. The building became one of the main references for the people, so much so that the entire surrounding district took the name of Terziere della Campana. The donzello of the Municipality was in charge of ringing the big [bell] to signal, in addition to extraordinary events, the canonical hours: Lodi (at dawn), Prima (around 6), Terza (at 9), Sesta (at 12) , Nona (at 15), Vespers (at sunset) and Compline [sic], before going to bed.












Where the bell was not within earshot, it was the position of the sun in the sky that marked the time or, if the sky was cloudy, the intensity of the light was enough to mark the slow life of our ancestors.


Then, with the spread of mechanical clocks, one was installed below the bell. The task of supervising, maintaining and charging it passed to the moderator of the public clock [moderator: who knows if this name meant inviting the spheres not to be in too much of a hurry?]. It is likely that the imprecision of those first mechanisms made it necessary to put them back at the right time almost daily. This function, in the absence of today's time signals on the radio, could only be performed by a sundial. The symbiosis between the two instruments is confirmed by the coincidence of the presumable period of the installation of the mechanical clock (17th century) and the year (1658) engraved on the Fratta sundial.

The room of the discovery (outlined in green in figures 3 and 4) is located on the southern edge of the fifth of buildings of the current Piazza Fortebraccio, originally "Piazza Grande del Comune", in front of the Rocca "(platea comunis dicti castri ante cassarum) .
































There are several documents that allow us to deduce the evolution of the buildings on the corner between Piazza Fortebraccio and Via Alberti.

In the fourteenth century the building in which the sundial was found did not exist, but in its place there was an external ramp (figure 5), which was demolished (figure 6) when it became encumbered for the drawbridge that would lower towards the square from the Rocca under construction: in fact, among the works commissioned to Trocascio (27 May 1385) there was also that of demolishing it and rebuilding it inside ("Eo Trocascio I promise ... remove the staircase of the podesta's palace and remake it inside the said palace or elsewhere, so that it does not harm the cassaro [Rocca] ").










































Figures 5 and 6 show details regarding the rear building, towards the west, taken from deeds of the notary Nicola di Antonio. First of all it belonged to the Municipality, as shown in a document dated July 1443: "... in the square of said castle, in front of the Palazzo del Podestà and the Rocca (... in the stalls dicti castri ante palatium potestatis et arcem)" ...; in 1448, "in the Town Hall and residence of the said Podestà of the said Castle, in the upper room of the said palace (... in the palatio Communis et residentiae dicti potestatis dicti castri in the upper room dicti palatii) ..." (1). In another act of the following year we speak of the "lower room" (2). He refers to "upper room" in acts of 1464 and 1466 (3). It is therefore assumed that in the building there was a large room on the ground floor (current service entrance to the theater in Via Alberti, 22), which could be used for the meetings of the City Council, and an apartment on the first floor (with entrance at no.20 ) in use by the Podestà, which was accessed by an external staircase. Today the new staircase, whose intrados is visible just to the left of the entrance at no. 22, allows you to go up to the first floor from the entrance to n. 20 of Via Alberti.

A map by Anonymous dating back to 1730 (figure 7) shows us that the building where the find was not yet existed. The same indication comes from a drawing by Fabretti of 1780 (see final note), which also highlights the existence of a chapel annexed to the Monastery of the Nuns of Castelvecchio, indicated in figure 4.
























On the basis of the clues described above, I tried to reconstruct the events of our sundial.

In the first place, it is presumable that it was not part of the religious complex adjacent to the site of the discovery. In fact, the monastery of the Nuns of S. Maria di Castelvecchio had been suppressed at the end of the fourteenth century, two centuries before the construction of the sundial. Furthermore, the hours engraved on the surface of the octagon - Italic hours for civil use, rather than Italic for bells used for bell towers - support the hypothesis of a civil use and exclude the religious one.

A further trace: the small distance - a few tens of meters - of the room where the sundial was found from the civic tower of the Bell (and, later, of the Clock), suggests that the two systems of time measurement were in close symbiosis, confirmed by the coincidence of the respective construction periods.

The adjacency to the hall of the municipal council and to the seat of the Podestà suggests that it was exhibited somewhere in the square. The window sill of the "upper room", on the first floor of via Alberti 20, was probably the ideal point (figure 8) on which to display it in the horizontal position for which it was conceived. In fact it was sunny and protected, within reach of the highest authority of the castle.

















Mauro Bifani confirmed the validity of this hypothesis, found in other situations: inside the Sperelliana library in Gubbio, the sundial originally exhibited on the window is preserved, where traces of the well-oriented seat in which it was positioned remain; also in the Marches there is another, still in its place, which makes a good impression on a window sill.


The Platonic marriage between the solar instrument and the mechanical one, not consummated due to the distance of their respective residences, went into crisis in the nineteenth century, for various reasons.

The signs of old age arrived for the bell tower: in 1815, due to a subsidence of the foundations, it had been shortened, but with poor results: in 1820 it was completely demolished. But the clock was too important for the inhabitants of Fratta to do without it: at the same time a new tower was built (figure 9) in the central square - Piazza del Grano - in front of the current Town Hall, which had become the new center of gravity of the country. But the purchase of a new watch resulted in the death sentence of the old one, already in bad shape due to worn and rusty wheels.















The solution proved to be precarious because, after just half a century, in 1873 it was decided to enlarge the Piazza del Grano to give air to the current Piazza Mazzini; to make room, the fledgling tower was sentenced to death at the bitter age of 53. As can be seen, even in the past, not all choices were far-sighted.


Even for the sundial, widowed, the end loomed. To put a load of eleven there was the construction of the building at number 9 of Piazza Fortebraccio, as shown by a plan of the Gregorian Cadastre (figure 10) dating back to the period 1830-1850. From that moment on, the area assumed its current shape.




















The new construction "blinded" the window of the upper room where the sundial had lived, depriving it of its function. As a result, she was fired and evicted. He found refuge in the room where it was found, downgraded to a simple decorative element, albeit with the advantage of protection from the elements. Subsequently it raged, segregating it under the plaster. In short: in addition to life, the solar instrument and the mechanical one also seemed united in the end. But there was a surprise for the sundial.



Rediscovered in the third millennium, by the owner the sundial has been moved to its natural environment, outside a pleasant cottage in the sweet Umbrian countryside.

Although hanged vertically - contrary to its nature to relax horizontally - and with a random orientation with respect to the cardinal points, it is very happy to have rejoined the sun, remaining an interesting testimony of the history of Fratta.



Since the appetite comes with eating, I was intrigued to know who took over the sundial and the clock her husband, in the task of marking the time of our community after the demolition in 1872 of the ephemeral tower in the square.

Nobody could tell us better than Egino Villarini, who joined me at the PC keyboard.

In November 1876 the works for the enlargement of the old Piazza del Grano were completed, decided by the Municipality due to the increase in the volume of commercial activities, the growth of the population and the fact that it "was in a cramped confined space. "; last but not least, "the not very decent appearance of the buildings" which impoverished the Sorbello palace, seat of the Municipality.

The square (now Piazza Matteotti) took the name of Umberto I. A new bell clock was placed in the center of the building opposite the town hall (Figure 11). It was operated by large stone blocks which, hung from a chain, descended from the top floor to the ground, where the Post Office was located. In more recent times, the task of turning the crank to raise the weights could not fail to be entrusted to Gino Vannoni, watchmaker. It was the engineer Villarini himself who relieved him of his duty by automating the operation.



















In 1918, the primary school clock (Fig. 12) entered the life of the people of Umbria, with the task of informing the schoolchildren, at a quarter past 8, that it was time to set off and, at 8:30, that the it was closing. Today, clocks are everywhere - on the streets, in the squares, on everyone - to synchronize with the hasty rhythms of modern life. But it would be quite another sensation to respond, as yesterday, to the call from the voice of the school: a solemn rite of the community, testifying to the collective concern reserved for the process of integrating young people into the cycle of social life. Those familiar tolls were then perceived by everyone, thanks to the silence in the town and the concentration of the houses; today they would perhaps be suffocated by the noise of cars and muffled by the remoteness of the suburbs. Yet they could represent the symbol of a cohesive and harmonious community, sickened by decades of excessive individualism.

They would be especially appropriate in these times of seclusion.
















Regarding the volume of Fabretti, I want to tell a singular detail. Together with Amedeo Massetti we were consulting it in the Augusta Library in Perugia, when we came across a map referring to “Fratta” (figure 13, left), but it appeared totally different from that of our country. We thought it was the result of an error, also likely due to the low quality of the drawing, attributable to a novice author. After various considerations, we discovered the dilemma: the image had been copied against the light on a window pane, but on the wrong side. It was enough to do the opposite operation - this time with the PC - to get the right drawing, but with the name “Fratta” inverted (figure 13, in the center). An enlargement of the plan (figure 13, right) reveals the lack of the building of the find. There is also an interesting detail: a small church is marked with a cross (barely perceptible) - indicating that it was still officiated - annexed to the adjacent monastery of the Nuns of S. Maria di Castelvecchio.























Arch. Notar. di Umbertide, Notary Nicola di Antonio, acts 1448 - 1450, cat. 276/74, card 11 / v

Arch. Notar. di Umbertide, Notary Nicola di Antonio, acts 1448 - 1450, cat. 276/74, card 99 /

Arch. Notar. di Umbertide, Notary Nicola di Antonio, acts 1464 - 1466, cat. 283/5, cards 10 / r, 120 / v, 225 / v



For this little research, I have made extensive use of the work of friends:

  • Renato Codovini, generous initiator and prompter for all researchers of local history, who exhumed historical documents otherwise destined to remain buried in the archives;

  • Amedeo Massetti, unforgettable friend and perfect citizen;

  • Egino Villarini, an inexhaustible source of the innovations introduced in the country, with the reliability and details of having been the protagonist;

  • Adriano Bottaccioli, who imagined the missing pieces of our country from every point of view, reconstructing them with the artist's ability and with the affection of the ex-emigrant;

  • Mauro Bifani and Manlio Suvieri, who provided the technical information necessary for the reconstruction of a plausible history for our sundial.

  • Fabio Mariotti, who checked the text (once I relied on Amedeo), enriching it with images.

1A0 Meridiana.PNG
1A1 Figura 1 Piazza Fortebracci.PNG
1A2 Adriano Torre della campana.PNG
1A3 Scenario attuale con didascalia.PNG
1A4 Scenario attuale Via Alberti.PNG
1A5 Scenario al 1385 con didascalia.PNG
1A6 Scenario dopo 1385 con didascalia.PNG
1A7 Pianta anonimo 1730.PNG
1A8 Scenario al 1658.PNG
1A9 Adriano Torre orolgio in piazza.PNG
1A10 Catasto Gregoriano 1830.PNG
1A11 Orologio di Piazza Matteotti.jpg
1A12 Orologio Scuole elementari.jpg
1A13 Pianta Fabretti.jpg
La Meridiana della Piazza Grande della Fratta
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