Engineering Rome

Evolution of Construction in Rome’s Historic Districts

Rome is one of the oldest cities in the world, and so it is full of history that is built into its very stones. It is a metropolis of culture and tradition that has evolved over thousands of years as people lived and died there; each generation building their lives on those who came before them. By walking through Rome, one can track the passage of time through the different architectural styles of the eras. Rome’s organic evolution occurred through the history of building on the bones of what was already there. There was no need for people to tear down the entirety of an old structure to build a new one in its place, and so buildings were constructed to incorporate the structurally sound parts of the original building into the new one, along with anything else that the owner wanted to keep for aesthetic reasons.

Rome, like any city, has evolved through concerns for practicality, and economics. The city as a whole shows how people work with what they have been given and adapt to the situation. People and builders made decisions based on what made sense for them at the moment, and not with any consideration of how it would play into history over time. A clear example of this is that without modern technology, it was not cost-effective to tear down an old building when it was possible to only change parts of it or build onto something else instead. As this city is just built upon the old, it is possible to track the history of construction throughout the years. One common thread throughout the different eras was that the builders used what they had available to them and repurposed everything they could. From bricks to entire walls or structures, everything was reused, and so, in many ways, this lead to the preservation of the older structures until they became historically relevant. The landscape of Rome has been shaped by trying to build something new while preserving the old. The Romans of the modern day are no different. Now it is laws that prevent them from tearing down any of the historic buildings and so, like their predecessors, they do their best to make the smaller cosmetic changes to a building to adapt it for better use, while not destroying what was there before. This has led to difficulties in construction, which has caused unique workarounds that now shapes the way construction functions in Rome today.

Construction in Ancient Rome and the Middle Ages

A basic understanding of Ancient Roman construction techniques is important to understanding Modern Rome and the way it evolved. Ancient Roman Ruins were the source of the reuse of materials and buildings in later years, so by examining what remains and what was moved, one can get an understanding of how roman construction evolved over the centuries. In ancient roman construction, bricks were used as a form for the concrete which was poured into a gap between two brick walls and provided the main structural support. This wall was then covered in either plaster or marble to create an aesthetically appealing facade. This construction technique is visible in the ruins of the baths of Caracalla shown in Figure 1 below. The section above the marble looks rough and full of holes, this is the exposed concrete that still has the marks of the bricks in it that have been removed. below this and at the top of the photograph, bricks are still visible as well. Then there is the decorated marble that only remains in pieces as the rest has been removed. This photo gives a good example of the layers of materials that were used in ancient roman construction.

Figure 1: Wall at the Baths of Caracalla

One way to set a date to roman buildings is to look at the stamps on the bricks. According to Adriano Morabito of Roma Sotterranea which was explained during a verbal conversation, bricks made in the Roman Empire were all stamped with the emperor of the time. Morabito explained how the only time one would expect to see a building with tricks that had different stamps would be at the death of an emperor when the old bricks from the previous emperor would get used up before the project would use the new bricks that the factories sent that had the new bricks. this reasoning was a purely economical choice as it made no sense to get rid of perfectly good bricks just because they had the wrong stamp. An example of a stamped Roman brick can be seen in Figure 2 below. The round stamp is partially broken where part of the brick has broken off. This photo gives a good example of what a classic Roman brick looked like. Compared to a modern brick, it is very long and wide but is also quite thin. This shape is a sign that the brick is from ancient Rome. Figure 2 also gives a good close-up look at roman concrete. It is full of large chunks of rock and other material and is filled in with the cement mix containing smaller aggregate in between.

Figure 2: A Stamped Brick in Ostia Antica

To understand the way that buildings and materials in Rome were reused, one must first understand the way that it started in the middle ages, the period when reuse was most prevalent. Upon the fall of the Roman Empire, major construction in the city of Rome stopped. The population greatly shrunk and the people still suffered attacks from outside invading forces. As seen in Figure 3 below, the population drop was drastic, and with so many people leaving in such a short period of time, the city would seem abandoned. With so many empty buildings left all over Rome, there was little need for people to build something entirely new. The people of the middle ages were able to adapt existing buildings to their uses. The official Fall of Rome is considered to be in 476, after the third gothic invasion of Rome and the overthrow of the emperor. As no Roman leader ever ruled from Rome again, it fell to those who were still in the city to keep fixing it up. This included some of the Byzantines who took over Rome, the later popes, and powerful families in Rome. These leaders oversaw the larger construction projects of the city. An example of this was in the sixth century AD when Rome was captured by the Byzantines. They were led by general Belisarius and then held the city against the goths during the gothic wars.  When the city was recaptured, Belisarius ensured that “his own soldiers repaired the damage [to the walls] in twenty-five days using ‘the nearest stones to hand’” (Coates-Stephens, p.169).  This practice of reusing the nearest available stone was a common practice in this period. There was no sense in bringing any new materials into the city when there were so many abandoned buildings already there. The practice of reusing materials is a staple of construction in Rome in the middle-ages.   

Figure 3: The Population of Rome Over Time. Source:

Almost every material that could be repurposed by the people of the Middle Ages, was. Many roman structures that remain have been stripped down to the concrete; the only material that cannot be repurposed into a new building. As seen above in Figure 2, a section of a wall in the Baths of Caracalla only has bricks on part of it along with a few pieces of marble. The rest of the wall is made of concrete with divots in it to show where the brick had been. The baths are known to have been covered with marble, and while a few pieces remain, they are only individual pieces, and most of the walls have been systematically stripped. This aligns with “The technique of re-using opus quadratum tufa blocks in conjunction with re-used bricks, the latter laid in notably undulating courses, has… been demonstrated to belong assuredly to the period from about 750 to 850” (Coates-Stephens et al, p.169).

One clear sign that a building in Rome was built during the middle-ages is that the bricks do not match. To secure enough bricks to build a new building, the people of the middle-ages would pull bricks off of ancient roman buildings, and it would make sense for them to use the ones that were easiest to reach, so they would not all come from the same source. The practice of using materials from different places is evident in some middle age buildings by the bricks they used. Roman bricks were made with the stamp that named the current emperor and their shape slightly changed over time. Buildings from the Middle Ages which are comprised of a collection of different-looking bricks, and bricks that have stamps from a variety of emperors, are ones where the builders had to go looking in multiple buildings to find enough bricks to build the building. Figure 4 shows a good example of how a wall from the Middle Ages looks. The narrow, skinny bricks have the same proportions as the stamped brick from Figure 3, which would place them as bricks made during the empire. The different colors and sizes of the bricks make sense when considering that these bricks were pulled off of older buildings. As people used the bricks that were on hand, not all of them would have been perfect. It feels safe to assume that if people are individually pulling bricks off a wall, then some of them would come off broken, and they would get used anyway. The color of the bricks can also be explained by the fact that they came from different sources. The color of the brick is based on minerals in the clay from which the bricks are made. There was no deposit of clay large enough to supply Rome with enough clay to last the entire time of the republic and the empire. It seems safe to assume that over time, bricks were made with clay from different deposits, so their colors would be different. This color difference is then a sign that the bricks were made at different times.

Figure 4: A Wall In Palazzo Pio

These People of the Middle Ages would live in the remains of roman buildings, sometimes adding to them or just fixing them up until they no longer resembled the original building, even while some of the pieces were still in it. If an ancient roman building was well made and in good condition, it made for a good start to the building, and it was more affordable to incorporate parts of the older structure. This building method is the reason behind the layout of modern Rome. As buildings incorporated the footprints of older buildings, the city layout stayed practically the same over the centuries. While some buildings might have been torn down for one reason or another, there are still many places throughout the city where the footprint of roman structures can be seen. This paper will look at two such examples: The Basilica of San Nicola in Carcere and Palazzo Pio, the site of the UW Rome center.

Basilica di San Nicola in Carcere – A Visible Passage of Time

The basilica shown in Figure 5 below is a clear example of the practice of building onto existing structures. The church is a mishmash of different styles and has been added onto at different points in time. This basilica gets its name from an accident in history. According to Rome’s official tourist website, Turismo Roma, the roman ruins that still stood there were “transformed into a prison during the Middle Ages (hence the name ‘in carcere‘, ‘in prison’).” (Turismo Roma, Basilica). In 1128, the basilica was built, and “it was dedicated to St. Nicholas, since the Greek community, devoted to the saint, lived in the area.” The name San Nicola in Carcere translates to Saint Nicolas in prison, and the name is entirely due to some mix-up in the past where the old use of the building got mixed up with the new basilica and they were combined into one name. This basilica is a great example of how it is possible to walk around Rome and guess how old different parts of the same structure are based on knowledge of construction methods and architecture to see how they were reused.

Figure 5: Church next to Teatro di Marcello

The columns on the side of the building along with the marble beams on top are part of a roman ruin. According to Turismo Roma, these columns are part of three Roman Temples that stood in the ancient Forum Olitorium during the days of the Roman Republic. As this building is right next to the remains of the Teatro di Marcello, it is likely that the ruins were preserved by being incorporated into the church, just like the theatre was incorporated into a building that still stands today. While the columns have been filled in between them, likely to provide structural support over time, the ancient part of this building is still visible even after additional brick structural support was added on the sides.

The bell tower on the church was most likely built in the late middle ages. It is likely that this was part of the structure that was added in 1125 when it became the basilica of San Nicola. This guess is derived from the fact that it is still standing and built in the style that it is. it is unlikely that the prison that stood here before the church would need a bell tower, and this church tower must have been built before the thirteenth century as it was not done in the gothic style that was popular at the time. This tower was also not built after this time because it would have been made to match the classical façade had it been built afterward. The tower was not built in the brick pattern where some rows stick out further to allow for marble attachment. According to Stefano Croce, the tour guide for Urban Safari in Venice who is an architect and has studied historic structures, the distinct shape of brick where it forms the zigzag is common for historic walls that had marble attached to them, as it made the marble easier to secure. The lack of this pattern on the tower would have made it difficult to add a façade when the front of the church was redone.

The marble façade in the front of the church has the hallmarks of a late renaissance façade. The renaissance period lasted from the fourteen hundreds to the middle sixteen hundreds. The Renaissance period focused on a revival of classical forms and naturalism. The understanding of classical style came from two main sources: “the ruins of ancient Classical buildings, particularly in Italy but also in France and Spain, and the treatise De architectura (c. 27 BCE; “On Architecture”) by the Roman architect Vitruvius” (Scranton, 2022). The Renaissance period was marked by a revival of classical Greek and Roman architectural details like the triangular roof at the top of the façade or the columns with their tops that seem to be styled after the ionic style. This church, while still having the characteristics of the renaissance style, is more ornate and stylized, which is a sign of the late renaissance style as it starts to evolve in the baroque period. According to Scranton, the late renaissance period, 1927-1600, is marked by taking roman architecture and finding a creative way to alter it in a stylish manner. Based on architectural style, this would place the church into the late renaissance period as a bit of baroque style is bleeding in as well. This placement based on appearance is matched by the history of the church, as it was partially “rebuilt and enriched in 1599, by the architect Giacomo della Porta” (Turismo Roma, Basilica).

The part of the structure at the back of the church appears to be the most modern, or at least the most recently redone. The plaster siding that is then painted appears to be in good condition. Based on other buildings around Rome, the plaster at least is most likely from the last two centuries, and the paint, while faded, is even newer. This guess of the age of remodeling matches with the history of the basilica as “it was freed in 1932 from the buildings that were attached to it (Turismo Roma, Basilica)

This church is a great example of how Rome is constantly evolving by building on the remains of what was already there. Whether this was to use ancient Roman ruins to proclaim one’s power or status, to use it for architectural purposes, or just for practical purposes, Rome became a city of remodeling and reuse. This has continued to a point where most buildings in the old parts of the city are built on the ruins or incorporate some part of an older building, and so are historical. Thus, Rome has become a city where it is difficult if not impossible to build anything new, and so modern roman developers must figure out how to repurpose and remodel what is already there.

The UW Rome Center – A Case Study

For a great example of how a building grows and changes over time, but still keeps aspects of the original, one needs to look no further than the UW Rome Center, located in the Palazzo Orsini Pio Righetti or more simply called Palazzo Pio, in Campo di Fiore.

The History of the Building

The Palazzo Pio is built on the remains of the Temple of Venus, which was part of the Theatre of Pompey, the site of the death of Julius Ceasar. The Temple of Venus was placed at the top of the arch of the theatre. The Theatre of Pompey was “the first permanent theatre in Rome, built in the Late Republican period, and never surpassed in sheer size in any part of the Roman world at any subsequent period” (Sear, p. 539). While it was illegal to build a permanent theatre at this time in Rome, Pompey said that he was building a temple for his patron goddess Venus and that the theatre was part of the temple. The Roman Senate could not stop this project for fear of offending the goddess, so they allowed the temple and theatre to be built. It was an imposing and massive structure in this city. It is estimated that “the top of the Temple of Venus would have exceeded the level of Piazza del Campidoglio by 18 m” (Sear, p. 539). As can be seen in Figure 6, the temple consists of four massive stories, and it was the tallest point in the theatre. This structure is so tall, that even with the rising of the ground due to sedimentation, much of the building would tower over Campo di Fiore today, had it not been enveloped by other buildings.

Figure 6: A 3D model of the Temple of Venus by Lasha Tskhondia

Palazzo Pio stands upon the remains of the Temple of Venus. Its layout perfectly aligns with the shape of the northern part of the Temple of Venus, which can be seen in Figure 7 as the rectangular shape sticking out of the theatre at the top of the arch, and the footprint of the Palazzo Pio is the red quadrangle. The letter “A” on the map marks the approximate point from which Figure 8 was drawn.

Figure 7: Map of the Streets of Rome, overlayed with the known ruins of the theatre of Pompey. Map source:
Figure 8: Palazzo Pio painted by Giuseppe Agostino Pietro Vasi in 1754, Source:

No clear record of what happened to the Temple of Venus after the fall of Rome could be found, but around 1150 AD, the Orsini family acquired the land and built a large palazzo that incorporated the remains of the old temple. This is evident because the footprint of the current building still has the same footprint as the old Temple of Venus, and bits of the old temple are still visible in the building. One such example is the column that is seen in Figure 9, which is part of the basement of Palazzo Pio which is now occupied by a restaurant. The Palazzo which was built in 1150 AD was known as Palazzo dell’ Orologio due to the large clock tower that was a part of the structure. The building in its current form was constructed in 1450 by “Cardinal Francesco Condulmer, nephew of Pope Eugene IV Condulmer (1431-47)” (Turismo Roma, Palazzo). It eventually passed into the possession of the Pio family, who were the lords of Carpi. In the seventeenth century, the Pio family enlisted the services of Camillo Arcucci to remodel the façade, which included adding eagles and lions to the windows.

Figure 9: A column in the basement of Palazzo Pio

Since this reconstruction, not much has changed. As is visible when comparing Figures 8 and 10, the outside façade looks the same. Since the change of façade in the eighteenth century, all of the remodels have moved inside as the building has been adapted to the needs of the various people occupying it. According to Turismo Roma, the building was passed down through various owners and uses including the banker Righetti, Giovanni Borgi-who turned it into an orphanage, and eventually, in the 1980s, the UW Rome center began to occupy multiple floors in a long-term lease.

Figure 10: Palazzo Pio as it appeared in September 2022

Evolution of Palazzo Pio

Every time the building has changed since the construction of the Temple of Venus, a newer version of the building has been added onto the old one. Not only is this apparent in the way the building has kept its shape, but bits of the older buildings are still visible.

The clearest remnant of an older building is the brick wall that can be seen as exposed brick walls on the third floor of Palazzo Pio and is shown in Figure 11. Based on knowledge of Middle-Ages construction, an educated guess would say that this is from the remnants of the Palazzo dell’ Orologio, and maybe even incorporates part of the structure that likely was built onto the Temple of Venus after the fall of Rome. The clearest sign of this is the bricks that were used in the walls. Figure 4 is a close-up image of the back side of the wall seen in Figure 11. The bricks are a mix of different sizes that show that they were added onto or remodeled at different times. The thicker ones were added after the thinner bricks as the thin ones have the hallmarks of ancient Roman bricks. The closeup photo in Figure D shows the long, narrow bricks that are typical of the ones made in the roman empire. The ones in this wall are all different sizes and colors, which is generally a sign that they were removed from roman ruins. Ancient Romans used bricks all from the same factory in their project, so matching bricks is a sign of roman empire construction.

Figure 11: A Brick Wall on the Palazzo Pio 3rd Floor

One other remnant of an older version of the building that can be seen is the exposed brick that is visible on either side of the façade. Multiple tourist websites, including Turismo Roma, named the exposed brick in Figure 12 as remains from the Temple of Venus. Some of these sources are less than trustworthy, but an analysis of the exposed brick can at least confirm it as a likely possibility. This zigzag pattern created by the brick is what was described by Stefano Croce as the shape used to make marble attachment easier. This is an unlikely shape for the middle ages as it would not make sense to add marble in this space on the building, as most decoration was internal and this pattern does not appear on the internal walls that are visible inside. It was impossible to get a closeup photo of the bricks in Figure 12, though it was possible to get a photo of the exposed brick on the other end of the façade. The bricks in Figure 13 do appear to be the narrow, skinny bricks that are a staple of ancient Roman construction. These components mean that it is indeed likely that these are remains from the Temple of Venus, though it cannot be said definitively here.

Figure 12: Palazzo Pio wall facing Campo di Fiore & Figure 13: Palazzo Pio Wall on the left side of front façade

Apart from the change of the façade in the seventeenth century, No records of the changes to the building until the UW Rome Center moved into the building could be found. The building has been remodeled twice since the UW Rome Center moved into the building in the building in the 1980s. The first renovation occurred right when the space was occupied, and the second one started in 2019 to 2022 with both the first and third floors completed at this time. Figure 14 shows the first renovation in progress. It is clear that the exposed brick that is still visible on one wall of the modern room continues in the other walls as well, it was just covered over. This was the renovation where the new metal beams were added to preserve the original look of the ceiling in this room. 

Figure 14: Renovation of the third floor of Rome Center in 1983-84, Source: UWRC archives

As the building is remodeled, it was done to fit the sensibilities of the time. The colorations and the aesthetic of the rooms made them more modern and elegant than they had been before. This was also the time when the building was adapted to fit the uses of the Rome Center. The remodel of the 1980s is in contrast with the one that was recently completed on the First and third floors. This new renovation was completed to both update the building and restore some of its original appearance. As can be seen in Figure 15, before the most recent renovation, the ceilings in the building were mostly simple and white. As can be seen in Figures 16, 17, and 18 below, the new renovation exposed original wood ceilings where they had been hidden by the old ceilings that had been placed below them. Some of the old frescos that were previously visible were also refurbished.

Figure 15: Rome center after the 1980s renovation. Source: UWRC archives
Figures 16, 17, 18: UWRC Ceilings, 2022

The treasure of this most recent restoration is the exposure of the historic details. In previous changes to the building, a new ceiling had just been added below them, so these older designs had been preserved and could later be displayed again. This preservation is a key factor in Rome’s culture of construction. In general, they do not destroy, they just cover things up, and when the original is popular again as the style evolves, they can just unbury it and show it off again.

Modern Construction in Historical Rome

Modern construction in historic parts of Rome is influenced by a variety of factors, but the main three are the laws, the economics, and the constructability constraints. There are multiple laws affecting construction in the historical districts of Rome. Amity Neumeister, the director of the Rome Center, stated in an email exchange that they were unable to make all of the changes they wished to the UW Rome Center because of the laws about preserving buildings. She explained that the government of Rome has an office that is responsible for ensuring the historical integrity of construction in the city known as the Supraintendenza. They are the ones who decide what changes can and cannot be made to a historic building. One rule that applied to the Rome center project was that they could not make any structural changes to the outside of the building, so they were prevented from adding a door onto a terrace where a window now stands. Internally, in historic buildings, the owners are unable to change the configuration of the rooms that are already there by removing any walls, even if they are just architectural ones. Owners of buildings in Rome have had to learn to adapt the space to fit their needs and just work with what they already have.

Neumeister explained that the Supraintendenza is also responsible for the color of the buildings in Rome, by only allowing a building to be painted the color it was “originally.” This can lead to some difficulties as there might not always be a record of the building’s original color. Figure 19 demonstrates the way that this law has a practical effect on the appearance of the city. The photo shows a combination of pink, brown, and orange walls with different degrees of fading, along with an exposed brick wall on a different building. This photo is an accurate example of what many streets in the historic parts of Rome look like. They generally stick to this general color palate, and the plaster is faded to varying degrees on different buildings. Even on the exposed brick wall, there are signs of old plaster. The plaster by the upper story window is so faded and dirty that it blends in with the stone, and there is no way to know what the original color was. This color rule creates an interesting situation for the property owners because they have little choice about how their building looks. If they do not like the color that they must use then their only option is to let the plaster fade out. Plaster is used to cover buildings to protect the more expensive brick from the elements so that it lasts longer. When the owners decide to let the plaster color fade, they are running the risk of exposing the bricks to the elements and running up the cost of maintaining the building in the long term when the bricks eventually have to be replaced.

Figure 19: A Cross Street in Trastevere


I find the way that Rome has evolved into a city of reuse very interesting. It is a pattern that has continued for more than a millennia. As an American, this length of time is very difficult to understand, but it does explain the difference in thought processes. The Romans have always done it, so it’s much less of a bigger deal to keep reusing old buildings, but in the US, we have mostly built something entirely new. This is a form of sustainability that we do not think of in the US. Here, we build the newest buildings, with state-of-the-art innovative solutions and fancy new technology, but to create this, we create waste from tearing down the old buildings and all of the other waste associated with a construction project. Reuse in Rome is a different form of sustainability. By reusing and refurbishing buildings, and using the available materials on hand, they avoid creating a large amount of construction waste. This is a form of sustainability that I believe should become more prevalent in the US. Not only does it limit waste, but it preserves history. Many ancient roman ruins are buried within the walls of buildings that are still standing in modern Rome. It is unreasonable to expect that a city will remain frozen forever with everything preserved as it originally was. This form of reuse allows those old buildings to be honored and appreciated as they are given new life by still being put to the purpose that they were designed for.

Works Cited

“Basilica Di San Nicola in Carcere.” Turismo Roma, 21 Oct. 2021,

Coates-Stephens, Robert. “The Walls and Aqueducts of Rome in the Early Middle Ages, A.D. 500-1000.” Journal of Roman Studies, vol. 88, 1998, pp. 166–178.,

“Palazzo Pio Righetti.” Turismo Roma, 21 Oct. 2021,

Scranton, Robert L. , Kemp, Martin J. , Middleton, Robin David , Rice, David Talbot , Millon, Henry A. , Timmers, Jan Joseph Marie , Fleming, William , Hoffmann, Herbert , Bush-Brown, Albert , Zukowsky, John , Morrison, Hugh Sinclair , Martindale, Andrew Henry Robert , Stern, Henri , Cannon-Brookes, Peter , Coffin, David R. , Culican, William , Bloch, Raymond , Watkin, David John , Voyce, Arthur , Boardman, John and Millikin, Sandra. “Western architecture”. Encyclopedia Britannica, 22 Mar. 2022, Accessed 17 September 2022.

Sear, Frank. “A New Monograph on the Theatre of Pompey.” Journal of Roman Archeology, vol. 26, 2013, pp. 539–542. Cambridge University Press, Accessed 13 Sept. 2022.

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