The external size of the London amphitheatre was approximately 100m long and 85m wide. The arena (60m x 40m) had curved perimeter walls on which tiered wooden seating would have been constructed.
The first amphitheatre was built entirely of timber in about AD74. It was upgraded in about AD120 when ragstone and tile walls replaced timber for the arena wall and main ceremonial entrances in the west and east. These stone walls would have supported the timber framework for the tiers of seating above.
The entranceway was the main entrance into the arena, while spectators entered through external stairwells. These walls, never higher than about 2.5metres, provided a facing for the sunken arena, while the rest of the amphitheatre remained in timber. Elements of brightly-coloured wall plaster from the arena wall and marble inlays and mouldings from the structure indicate that it must have been an impressive building.
Two small rooms, or antechambers, built on either side of the entranceway, had doorways both from the passage and from the arena. They may have held shrines or served as waiting rooms for those about to take part in events in the arena. Slots cut into the stone arena threshold of one of the rooms may indicate that it had a timber sliding trap-door which could be raised to release wild animals into the arena.
A central wooden drain ran beneath the main axis of the arena and under the length of the entranceway. Both were covered by timber and would have been covered by sand. A stone-lined gully ran around inside the arena wall.
The main drains included timber-lined silt traps, tanks where silt and rubbish could collect. The drains connected up to a main drainage system outside the entrance of the amphitheatre. These drains were well-maintained during the life of the amphitheatre, being repaired and replaced since their maintenance was essential to keep the arena dry and functioning.
The arena was set 1.5m into natural ground and made of a bed of rammed gravel mixed with hard pink mortar, overspread by a thinner layer of soft sand. Earth dug out from the construction of the arena was used to form oval banking that supported the timber framework for the seating. It is estimated that London’s amphitheatre would have held about 6,000 – 7,000 spectators at a time when the population of London may have been about 20,000-30,000.
The amphitheatre was abandoned in the early 4th century. Some of the stone from the walls was removed and the arena became damp and derelict and seems to have become the town’s rubbish dump in the late Roman period.
For details of what can be seen now, see about the Amphitheatre in Londinium Today and Arena entertainment in Londinium Lite.