What Was the Colosseum For? Games, Crowds and the Politics of Rome

Nero had used the ground for the lake of his Golden House, a palace complex that swallowed the centre of Rome after the fire of 64 AD, and when the Flavian dynasty replaced him after the civil war of 69 the new emperor Vespasian drained the lake and gave the site back to the people in the most public way available. The money came from the sack of Jerusalem in 70 AD, and the labour, in part, from the Jewish prisoners taken there; an inscription reconstructed in 2001 records that the building was paid for from the spoils of war. Vespasian died before it was finished and his son Titus opened it in 80 with the hundred days of games; Domitian added the top storey and the underground. Its proper name is the Flavian Amphitheatre, and Colosseum came later, from the colossal statue of Nero that stood beside it.

The Colosseum is an ellipse 189 metres by 156, 48 metres high, with an arena of 83 by 48 metres, and its outer wall alone used 100,000 cubic metres of travertine held together by 300 tonnes of iron clamps, whose holes pock the stone where medieval scavengers dug them out. The structure is concrete vaults faced in stone and brick, and its engineering is the crowd:

• •Eighty numbered arches at ground level, each leading to a stairway, so that a spectator's ticket, a shard of pottery with a number, sent them to their gate, tier and seat, and the whole crowd could leave in minutes
• •Seating by rank: the emperor and Vestals at the arena's edge, senators on marble seats with their names carved in, knights above, citizens above them, and women and the poor on wooden benches at the top
• •A canvas awning, the velarium, rigged from masts around the top by a detachment of sailors from the fleet to shade the seats
• •The hypogeum, a two-storey basement of corridors, cages and lifts beneath the wooden arena floor, from which animals and scenery were raised through trapdoors by winches and counterweights
• •Fountains, latrines and, on the evidence of seeds found in the drains, snacks of figs, grapes, olives and nuts

A day of games had a programme. The morning was the hunt, in which trained fighters killed animals shipped from the empire's edges, lions, leopards, bears, elephants, hippopotami and ostriches, in painted scenery of forests and hills; the emperor Commodus shot a hundred bears in a day from a walkway. Midday was executions, in which condemned criminals were killed by animals, burned or forced to fight each other, sometimes staged as scenes from myth with the criminal as the dying hero. The afternoon was the gladiators, and the gladiators were the point: trained fighters, mostly slaves and condemned men but some free volunteers, matched by type, the heavily armoured murmillo against the net-and-trident retiarius, fighting singly to a decision that the crowd shouted and the sponsor of the games gave. Most fights did not end in death, since a trained gladiator was expensive, and studies of gladiator cemeteries suggest that perhaps one fight in five or six was fatal; a fighter who survived three years could win his freedom, and a few became celebrities whose names are scratched on walls in Pompeii.

The games were politics. A Roman emperor ruled with no constitution and no police force worth the name, and his position depended on the army, the senate and the people of Rome, of whom the last were a million strong, largely idle, fed by the state grain dole and capable of riot. The satirist Juvenal's line that the people wanted only bread and circuses was a complaint, but it was also a description of the deal. The emperor gave games, sat in the front, was cheered or booed, and heard petitions shouted from the stands; the crowd at the Colosseum was the one place a Roman could address the ruler of the world and expect an answer, and the emperors who gave the most games were the ones most anxious about their standing. The killing was part of the message: the animals were the empire's reach, the criminals its justice, and the gladiators its virtues, courage and contempt for death, performed by the lowest people in Rome for the highest.

Gladiator fights ended in the 430s, under Christian emperors who had come to find them impious, and animal hunts continued until 523. Earthquakes brought down the south side in the Middle Ages, the stone went into palaces and churches, including St Peter's, and the arena was in turn a fortress, a quarry, a workshop and a garden of exotic plants that had arrived as seeds in the animals' fodder; the popes consecrated it as a shrine to the Christian martyrs in the eighteenth century, which stopped the quarrying, though the evidence that Christians were martyred there is thin. It receives seven million visitors a year, the underground was opened to them in 2021, and a retractable arena floor is planned to cover the hypogeum again. It is the image of Rome on every postcard, and the building whose purpose was to let an emperor and a million people look at each other.

The Colosseum was built by the Flavian emperors from 72 to 80 AD, on Nero's lake with the spoils of Jerusalem, to hold 50,000 Romans for a programme of animal hunts, executions and gladiator fights whose purpose was political: the games were the emperor's gift to a city whose consent he needed and the one place the crowd could answer him. Its numbered arches, ranked seating, awning and underground lifts were engineering for the crowd, the games ended in the fifth and sixth centuries, and the shell survived as quarry, fortress and shrine.