As we’ve seen the Roman Arch moved things along quite a bit architecturally. But with a little innovation they increased the utility of the masonry ten fold. The arch as a single entity is good for a doorway, window or portico. But if you wanted a larger covered space you need additional support.
The solution came in the form of barrel vaults and groin vaults. Barrel vaults are essentially a long extension of a single arch. They form a long tunneling effect. Barrel vaults were utilized to build the large warehouses through out the city in ancient time, in order to store the vast shipments of goods coming into the city. Some of the most visible examples of barrel vaults are the ruins of the Basilica of Maxentius. To see them in person, you realize what a large open space they really are. Seen from both the Forum and Via dei Fori Imperiali, it’s an imposing structure.
Groin vaults are when two barrel vaults intersect at ninety degree angles. With the combined strength of four posts or piers, groin vaults require less buttressing and there for are an even sturdier structure. The groin vault heralded many of Rome’s greatest building projects. Today, one of the most important places you can see groin vaults is at the Colosseum. Forming a continuous corridor around the arena, the groin vaults allowed the high ceilings and monumental stadium.
The arch is one of the simplest and most important architectural features you’ll see in Rome. They form an integral part to many of the ancient structures and churches in Rome and are something you would probably over look unless you know what you’re looking at. And since the arch is truly Roman, it deserves due diligence.
A Roman arch in it’s most basic sense uses compression from the weight of the structure above to hold the pieces together. Using accurately shaped voussiors and a carefully placed keystone the arch diverts the stress downward in a force called thrust. This increases the load bearing capabilities and let’s us build taller, grander structures.
Now, I’ve had that explained to me in several different classes so if you didn’t catch all that, or got distracted at the pronunciation of the word voussoir, don’t worry. Let’s just say that the arch was more effective than the two options we had before. Which looked something like…
Post and Lintel
The post and lintel system was used in ancient Greek and Egyptian architecture, as well as the famous Stonehenge.But as you can see, it requires large posts to support the considerable weight of the lintels. That limited the height of the the structure as well as the possibility of significant windows. With such a heavy structure to support, space couldn’t be compromised for windows except at the very top near the roof, known as clerestory windows. This lead to very dark interior. Also, if a post and lintel building had a solid roof, that too was made of stone. Supporting the roof required a forest of large columns known as hypostyle halls. One of the best examples of that can be seen at Karnak.
The other option was a Corbelled arch, where the stones gradually inclined until they met at the apex of the arch. You can see from the image that they were on the right track, but the corbelled arch just wasn’t self supporting like it needed to be.
The Roman arch offered much greater architectural flexibility, and could withstand greater pressure. For the first time it offered the availability of a an open space. But even arches had limitations. It would require further innovation before many of the grandest spaces would be possible.
Evolution of an arch
The Temple of Portunus is a favorite of art history textbooks as a model of Ionic architecture It’s a 1st century BCE structure dedicated to the God of keys, ports, door and harbors. The raised platform, portico and single stairs are all signs of Etruscan influence, but after that the structure is Greek. Built of travertine and tuffa, the stone was originally plastered to imitate marble. This is another one of the temples that was eventually converted into a church.
The Temple of Hercules Victor located on the Forum Boarium is a Roman temple to the god Hercules, built a circular Greek style known as peripteral, encircled by a colonnade. The earliest surviving marble structure left in Rome, the build was erected in the 2nd century BCE of travertine stone and tuff foundations. The fluted columns are again indicative of the Greek design, as the Etruscan style would have favored unfluted columns. Corinthian capitals top each of the lofty columns. The fact that the Temple remains today can be attributed to the Papal Bull of Innocent III, who decreed the temple be converted in to a church in the 12th century. Holy places stay holy, and therefore protected as did the Temple of Portunus and the Pantheon.
The Forum Boarium lies at the base of the Capitoline, Palatine, and Aventine hills where the small river Velabro used to flow into the Tiber before the area was drained by the Etruscan Kings. A historically significant area, this was where the Shepherd found Romulus and Remus, and where the first Romans set up a market on the banks of the Tiber. Boats would tie up here to unload cargo, specifically cattle, where the Forum get’s it’s name. The center was supplied with goods by the port located nearby on the Tiber. Roads flow in all directions from this point to carry goods in to the city. As with any center in ancient Rome the religious centers are not far. Anchoring the public space are the Temple of Hercules and the Temple of Portunus.
Today, Rome’s most ancient market is known as the Piazza Bocca della Verita, “Mouth of Truth” after the stone mouth located under the porch of Santa Maria in Cosmedin. It’s an open, airy park around the corner from the hubbub of the Capitoline Hill and Forum. There is a small park and fountain between the two ancient temples and a view of the Tiber and Tiber Island is just across the street. If you keep walking along the Palatine Hill you’ll come upon the ancient track of Circus Maximus. The athletically inclined can jog a lap, or stage a foot race for your kids and let them burn off a little energy. All in the name of history of course.
The Capitoline Hill is situated between the Palatine and Quirinal Hills. It overlooks the Roman Forum to the Southeast and the Campus Martius to the Northwest. The smallest of the core Seven Hills, the Capitoline was one of the most defensible given the steep rise of the hillside. The hill acted as a fortress during the early stage of the Roman civilization and it was this hill that the Sabines crept up before they bribed Tarpeia to let them in the gates.
During the Etruscan rule of the Period of Kings plans were made for a temple to Jupiter Optimus Maximus, Jupiter the Best and Greatest. Measuring 55 meters wide and 60 meters long, remains of the foundation can be seen today in the Capitoline Museum.
The Capitoline Hill today.
After the abandonment and decline of Rome, much of the ancient knowledge was lost. Amongst other things, the recipe of cement was lost and care of the city’s vital aqueducts fell into disrepair. This caused the locus of the city to switch from the southeastern side of the hill, the Forum, to the north western and Tiber River side, what is today the Piazza Venezia.
Into the Middle Ages, the Hill remained in disrepair, earning the nickname “Goat Hill.” Santa Maria in Aracoeli was constructed in the 12th century over a temple constructed by Augustus. In 1536 Pope Paul III decided to spruce the city up before the arrival of Charles V, Holy Roman Emperor. He recruited Michelangelo to recreate the area, and the result is the Campidoglio we see today. Along with the Victor Emmanuel Monument, a small collection of Roman insula, and Santa Maria in Aracoeli, the Capitoline forms a miniature timeline of Rome’s architectural history.