Ten years, three emperors
The emperor Vespasian began the amphitheatre around 70-72 CE. His son Titus opened it in 80 with a hundred days of games, and his younger son Domitian finished the upper parts and the rooms under the arena. The full timeline, year by year, is set out in when the Colosseum was built. What matters here is the speed: a building about 189 by 156 metres, with room for an estimated 50,000 spectators, was usable within a decade.
A site already cleared
The builders did not start on crowded ground. After the fire of 64 CE, Nero had taken the valley for his vast palace, the Golden House, with an artificial lake at its centre. Vespasian drained the lake and put the amphitheatre in its place. The poet Martial praised the change: a private pleasure ground had become a gift to the Roman people. The lake bed gave a large, open plot, and the clay beneath could take a massive ring of concrete foundations.
Money from Jerusalem
A project this large needed cash. In the 1990s the epigrapher Géza Alföldy studied the holes left by the bronze letters of an inscription found in the Colosseum and read the original text: Vespasian ordered the new amphitheatre built from the spoils of war. The war was the Jewish War, which ended with the sack of Jerusalem in 70 CE. Many historians think prisoners from that war were among the labourers, although no ancient text says so. Skilled builders, stonecutters and engineers did the precise work.
A frame of stone, filled later
The secret of the speed was the order of work. First came the skeleton: piers of travertine, a hard limestone quarried at Tivoli, about 30 kilometres away. More than 100,000 cubic metres of it were brought to Rome, and the blocks were held together with iron clamps, some 300 tonnes of metal in all. When the clamps were pulled out for scrap in the Middle Ages, they left the holes that still pit the walls.
Once the piers stood, the spaces between them were filled with lighter materials: blocks of tufa on the lower floor, brick-faced concrete higher up. Concrete vaults on the piers carried the seats. Each material went where its weight and strength suited it, and the same bay could be repeated 80 times round the ring, which made the work quicker to plan and to supervise.
Several teams at once
Archaeologists have noticed small differences in the details from one part of the building to another. The usual explanation is that the work was split among four contractors, each building one quadrant from one of the four main entrances. The engineer Giuseppe Cozzo argued that work went on above and below the seating at the same time. Both ideas are hypotheses, but they explain how a building of this size could rise so fast.
The finished building sorted its crowd by rank, from senators by the arena to the poorest spectators at the top, a plan explained in what the Colosseum was for.
After the games
Shows were held there until the sixth century. Later the building became housing, workshops and a fortress, and its name changed: “Colosseum” comes from the colossal bronze statue of Nero that stood nearby, and the name is recorded in the Middle Ages. An earthquake in 1349 brought down part of the outer ring on the south side, and for centuries the fallen stone was taken away for churches and palaces. In 1749 Pope Benedict XIV declared it a place sacred to the Christian martyrs, which helped stop the quarrying. Between 2013 and 2016 its facades were cleaned. It remains the largest of the monuments the emperors gave Rome.
Where to see it
The Colosseum stands at the eastern end of the Roman Forum, in the Parco archeologico del Colosseo, which also includes the Palatine Hill. The nearest metro stop is Colosseo, on line B.
Sources
- Parco archeologico del Colosseo, “Colosseo”.
- Suetonius, Vespasian 9 and Titus 7; Cassius Dio, Roman History 66.25; Martial, Liber spectaculorum 2.
- G. Alföldy, “Eine Bauinschrift aus dem Colosseum”, Zeitschrift für Papyrologie und Epigraphik 109 (1995).
- the-colosseum.net, “Building the amphitheatre”.
- K. Hopkins and M. Beard, The Colosseum (London, 2005).
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