Engineering Rome

Roman Construction vs. Ancient Ruins

1. Introduction

Construction can be a lengthy process. First, someone is assigned to design and plan a structure and the finances are worked out and the proper materials and machines are purchased. After construction works are officially hired the project is allowed to run its course and it can be expected to be completed around an approximate date. That’s probably how construction in Ancient Rome started off as; they had an abundance of accessible land and the Romans were constantly conquering more and more cities thus acquiring more land. The Ancient Romans were able to design and construct miraculous structures without the use and knowledge of all the formulas and rules modern engineers abide by today. Construction in modern Rome, on the other hand, can be sort of complicated. Central Rome is full of ancient ruins and artifacts, both discovered and well-preserved (i.e, the Colosseum, the Pantheon, the Arch of Constantine) and uncovered. Construction in modern Rome is complicated because not only do engineers have to plan and design around the ancient ruins that are all insanely popular tourist attractions, but it’s also fairly common for the engineers to encounter new ancient artifacts and ruins while digging or excavating new sites. These new and unexpected discoveries can cause major delays on construction progress and deadlines. Roman engineers today can’t just design a simple subway system that provides service throughout all of Rome, they can’t just plan on constructing a new building anywhere they want in Rome. They have to constantly take into consideration the presence of the ancient ruins and they have to make appropriate accommodations so that they don’t risk damaging any of the ruins – even those that have yet to be discovered.

This paper will attempt to cover the basics of comparing and contrasting ancient Roman construction vs modern Roman construction. The modern Romans have the additional factors of the existing structures to deal with when planning projects. The construction of the Metro Linea C is a great example of such additional factors since the engineers need to build around and under existing structures such as the Colosseum.

2. Planning and Design

Ancient Roman Planning and Design

Around 20 BC, a Roman military engineer and architect named Marcus Vitruvius Pollio wrote De Architectura[1], which is more commonly referred to as the Ten Books on Architecture (an excerpt of this book can be seen in Figure 2a). His book covers practically everything there was to know about Ancient Roman architecture and his book is also one of the few surviving sources on classical architecture. In De Architectura, Vitruvius covers topics such as the materials needed to build certain structures (and the way in which such materials could be created), water supplies and aqueducts, the many ways science has influenced architecture, etc. Vitruvius made it clear that any structure built needed to be “beautiful, stable, and useful” [2]. To Vitruvius and probably to the other ancient Romans that lived in that time period, architecture was a form of art. Architecture needed to not only take into consideration the physical surroundings of the people, but also the relevant intellectual and philosophical concepts. For example, in Book II Vitruvius suggests that engineers and architects fully grasp Socratic concepts and theories in order to really create valuable work and to completely understand how and why their designs will come to life.

[Figure 2a. These are two pages from Vitruvius’ De Architectura.]

Vitruvius wrote very specific details as to why and how certain structures should be built. For example, in Book V, Vitruvius explains the purpose of a forum and how they should go about constructing them. Chapter 1 begins with the claim that Roman forums would be used for gladiatorial shows and follows with the suggestions that “the size of a forum should be proportionate to the number of inhabitants” and that balconies should be incorporated in order to “…bring in some public revenue” [15]. Furthermore, in Chapter X, Vitruvius proceeds to write instructions on why, how, and when to build baths. Baths were public spaces used by the romans not only to bathe, but to play sports, exercise, and even watch opera and concerts. Vitruvius specified that the rooms for the hot baths should be “…lighted from the southwest…” and that the hanging floors should be constructed with the ground being covered with tiles with an area of approximately 1.5 feet squared and topped with pillars made up of bricks that are set two foot tiles away from each other.

Ancient Romans had an abundance of land to work with, especially during 117 AD when the Roman Empire reached its peak encompassing over five million square kilometers of land. With a growing population, it was necessary to start planning and designing structures that would help provide better service throughout the entire empire. For example, ancient Romans understood that adequate water supply was vital so they started to design aqueducts, wells, cisterns, and many more structures. In Book VIII of De Architectura, Vitruvius provides instructions on how to survey for water sources, how to test for ‘good’ water, and how to construct an aqueduct. He writes that water derived from masonry conduits, baked clay pipes, or lead pipes would be collected in central tanks; from those tanks, pipes will be used to supply water in public baths, private homes, basins, and fountains. Aside from these practical and innovative structures, ancient Romans also took the time to plan and design structures that were simply just to boast of specific victories and achievements [18]. The Arch of Constantine is a prime example of a marvelous structure that is technically not physically used in everyday. It was erected 312 AD by the Roman senate and it was officially dedicated in 315 AD to Constantine to celebrate his triumph in the Battle of Milvian Bridge[3]. This arch was constructed to be a part of the Via Triumphalis – the specific route taken by triumphant emperors and warriors. Roman engineers designed the arch to have three archways and to be decorated with several illustrations of Constantine and his numerous deeds. Today, it is not possible for vehicles to go under and through the arch.

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[Figure 2b. The Arch of Constantine can be seen clearly from the Colosseum]

Modern Roman Planning and Design

Modern Roman engineers have a more difficult time in planning and designing new structures or even just improvements on existing structures. Rome is a very complex and populated city and it is also home to some of the oldest ancient ruins in the world. Structures like the Colosseum and the Pantheon have stood against the test of time and remain in-tact and standing thousands of years after construction. Instead of being able to simply survey an open area of land, modern Roman engineers have to literally work around or under all the ancient ruins. Instead of building new structures altogether, modern Roman engineers seem to just work on improving or covering up the structures that the ancient Romans built. For example, a majority of the roads in Centro Storico are made up of sampietrini and provide an extremely uneven surface for drivers and pedestrians. These sampietrini roads have been in use for over 2,000 years and although the tourists love the authenticity these roads give to the city, the uneven surfaces have been quite a menace to native Romans. The roads cause noisy and uncomfortable transportation; the wheels of cars and buses hitting the stones produce a loud drumming noise and the buses also rattle extensively throughout the city. Moreover, the rattling of all the vehicles on the stones could potentially damage neighboring ancient ruins and sites. Instead of replacing these ancient Roman roads with different stones, Roman engineers today are working on just removing the cobblestones from the busier streets and paving the roads with tarmac and asphalt [4]. In order to keep some of the ancient Roman authenticity, the stones in Piazza Venezia (the square that connects the Colosseum and the Forum) will stay. In addition to the limitations in constructing new structures, modern Roman engineers also have to constantly be accompanied by archaeologists whenever they are excavating new sites. The archaeologists are there to make sure that the engineers do not damage any of the ancient ruins and they are also there just in case new ancient artifacts are discovered. The presence and need for archaeologists results in major delays in construction and production time; when an ancient artifact is discovered, construction is paused so that the archaeologists can determine the significance of the artifact and determine whether or not to put it in museum, re-bury it, or even destroy it altogether.

[Figure 2c. The gaps between the cobblestones in this image were in the process of being filled with asphalt.]

3. Construction Materials and Methods

Ancient Roman Materials


Ancient Romans used fired bricks for their structures and their bricks were stamped with the names of the current emperor when produced as a way to represent the date of production. In Book II of De Architectura, Vitruvius advises that brick used for construction be made up of white/chalky clay or red clay. Both white and red clay were claimed to be very light and very durable which were two beneficial characteristics because they enable easy transportation and handling. Vitruvius also explains that bricks should be made in either spring or autumn to get the best results. Creating the bricks during these two seasons ensures that they dry completely and correctly. Bricks made during the summer usually dry too quickly externally and do not dry enough internally.

[Figure 3a. These bricks can be found on the Aqua Claudia located in the Parco Acquedotti.]

Roman Concrete

Roman concrete is famous for its long-lasting durability and strength; the secret ingredient to their concrete was barely discovered in the 21st century [5]. The ancient Romans made their concrete by combining their homemade cement (which is made from lime, water, and volcanic ash – also known as pozzolan) with gravel. The addition of the volcanic ash in the cement resulted in the substance hardening under water and thus resulting in Roman concrete being more resistant to water than other materials. The cement, according to Vitruvius, must made from lime burned from white stones and the lime must be mixed with pit sand[6 ] in a ratio of one part lime to three parts sand. Roman concrete was commonly used to construct arches, domes, barrel vaults, etc. Roman concrete was also used to construct some of Rome’s most iconic historical structures such as the Colosseum and the Pantheon as shown below in Figure 3b.

[Figure 3b. This image shows the concrete exterior of the Colosseum.]


Travertine is a yellow limestone derived from calcium carbonate and it was a very popular material used in ancient Roman construction. It was capable of resisting stress with limited strain and so it made sense that it was commonly used in constructing arches. Travertine was also used in constructing the Trevi Fountain and for the pillars and radial walls of the Colosseum. Ancient Romans used travertine often because there was an abundance of this rock and it was also easier to remove and carry than other rocks such as marble.

[Figure 3c. This slab of travertine was observed during our trip to the Pacific’s Cava di Tranvertino.]


Marble[7] is an expensive and very elegant stone that was the direct result of the metamorphism of limestone. This extravagant stone was used in the Pantheon and in the construction of most sculptures and statues. Marble was also used in constructing the Arch of Titus [8]. In Book VII of De Architectura, Vitruvius explains that marble could also be used in stucco (a plaster used to coat wall surfaces). Broken pieces of marble are ground up and sifted in order to make fine and smooth stucco.

[Figure 3d. Here is an example of marble used in the sculpture of Cupid and Psyche at the Ostiense Museum.]

Ancient Roman Methods

Golden Ratio

The golden ratio (indicated by the Greek letter phi Φ) has an irrational value of 1.6180339…[9]. The golden ratio is the ideal ratio a structure’s dimensions should have in order to be the most visually appealing. The golden ratio involves separating a single segment into two, A and B, then A/B = (A+B)/A ≈ 1.618. Although the exact date of discovery and application of the golden ratio is unknown, it is evident that this ratio has been used by many artists, designers, engineers to obtain seemingly perfect symmetry and proportions for thousands of years. Some scholars believe that the Egyptians incorporated the golden ratio into the construction of their Great Pyramids. However, Vitruvius was the first to actually mention the concept and write the ‘formula’ for the golden ratio. One of the most famous examples of the golden ratio is Leonardo de Vinci’s “Vitruvian Man.” This drawing measures a golden ratio of 1.62 throughout the entire body.

Dry Stone

The method of building dry stone walls literally means using dry stones without any type of mortar to hold or bind them all together. The stones are just stacked up on top and against one another without any sort of support [10]. Vitruvius offers multiple suggestions on strengthening walls built with the dry stone method; instead of mindlessly stacking stones together, he suggested to place blocks alternately with either the longer or shorter side on the face of the wall. Even after the ancient Romans developed a strong mortar using limestone and pozzolan, they continued to construct walls using the dry stone method.

Modern Roman Materials and Methods


Travertine is still commonly used today; slabs of this stone can be used for interior design purposes. For example, someone could request to have their bathroom walls or floors consist entirely of travertine, there are also several pieces of furniture available that incorporate huge amounts of travertine – the Travertino Cava has a few pieces of travertine furniture that they will soon sell to their clients. In order to remove travertine from its quarries, engineers need to drill holes into the travertine and a diamond cable is looped through the holes to cut the stone. The diamond cable and the stones need to be constantly be lubricated with water to prevent extreme temperatures that might damage the stone and/or the cable. After the stone is extracted (this process could either take a few hours or a few days depending on the size and density of the travertine being extracted), the resulting slabs are then broken up into smaller pieces that are easier to handle. These slabs are then taken inside the factory where more engineers decide how to cut and split them. Engineers have the options of using either a guillotine or diamond saws to cut the slabs depending on what it will be used for and/or their clients’ requests. Instead of using travertine for enormous structures, modern Roman engineers use travertine mainly for flooring and wall-cladding.