The interior of the Colosseum, Rome (available only in b&w).
Seating
According to the Codex-Calendar of 354, the Colosseum could accommodate 87,000 people, although modern estimates put the figure at around 50,000. They were seated in a tiered arrangement that reflected the rigidly stratified nature of Roman society. Special boxes were provided at the north and south ends respectively for the Emperor and the Vestal Virgins, providing the best views of the arena. Flanking them at the same level was a broad platform or podium for the senatorial class, who were allowed to bring their own chairs. The names of some 5th century senators can still be seen carved into the stonework, presumably reserving areas for their use.
The tier above the senators, known as the maenianum primum, was occupied by the non-senatorial noble class or knights (equites). The next level up, the maenianum secundum, was originally reserved for ordinary Roman citizens (plebeians) and was divided into two sections. The lower part (the immum) was for wealthy citizens, while the upper part (the summum) was for poor citizens. Specific sectors were provided for other social groups: for instance, boys with their tutors, soldiers on leave, foreign dignitaries, scribes, heralds, priests and so on. Stone (and later marble) seating was provided for the citizens and nobles, who presumably would have brought their own cushions with them. Inscriptions identified the areas reserved for specific groups.
Another level, the maenianum secundum in legneis, was added at the very top of the building during the reign of Domitian. This comprised a gallery for the common poor, slaves and women. It would have been either standing room only, or would have had very steep wooden benches. Some groups were banned altogether from the Colosseum, notably gravediggers, actors and former gladiators.
Each tier was divided into sections (maeniana) by curved passages and low walls (praecinctiones or baltei), and were subdivided into cunei, or wedges, by the steps and aisles from the vomitoria. Each row (gradus) of seats was numbered, permitting each individual seat to be exactly designated by its gradus, cuneus, and number.
Arena and hypogeum
The arena itself was 83 meters by 48 meters (272 ft by 157 ft / 280 by 163 Roman feet). It comprised a wooden floor covered by sand (the Latin word for sand is harena or arena), covering an elaborate underground structure called the hypogeum (literally meaning “underground”). The hypogeum was not part of the original construction but was ordered to be built by Emperor Domitian. Little now remains of the original arena floor, but the hypogeum is still clearly visible. It consisted of a two-level subterranean network of tunnels and cages beneath the arena where gladiators and animals were held before contests began. Eighty vertical shafts provided instant access to the arena for caged animals and scenery pieces concealed underneath; larger hinged platforms, called hegmata, provided access for elephants and the like. It was restructured on numerous occasions; at least twelve different phases of construction can be seen.
The hypogeum was connected by underground tunnels to a number of points outside the Colosseum. Animals and performers were brought through the tunnel from nearby stables, with the gladiators’ barracks at the Ludus Magnus to the east also being connected by tunnels. Separate tunnels were provided for the Emperor and the Vestal Virgins to permit them to enter and exit the Colosseum without needing to pass through the crowds.
Substantial quantities of machinery also existed in the hypogeum. Elevators and pulleys raised and lowered scenery and props, as well as lifting caged animals to the surface for release. There is evidence for the existence of major hydraulic mechanisms and according to ancient accounts, it was possible to flood the arena rapidly, presumably via a connection to a nearby aqueduct. However, the construction of the hypogeum at Domitian’s behest put an end to the practise of flooding, and thus also to naval battles, early in the Colosseum’s existence.