The amphitheatre of Toulouse-Purpan is constructed on a filled structure, unlike those in Arles, Nîmes, and the Colosseum in Rome, where a hollow structure composed of vaults and pillars supports the tiers. The cavea (the rows of seats intended to receive the public) is fifteen meters wide. This area is separated from the arena by a wall and bound at the outside by a high wall covered in brick. The cavea is divided into equal segments compartmentalized by twenty-three arched horizontal corridors, the vomitoria.
The main entrance to the amphitheatre is located to the north of the arena and is 4.20 meters wide. The arch reproduces the height of the curved vault, which once covered the entry passage. The almond-like arena is sixty-two meters long by forty-six meters wide. Underneath this surface lies an underground network of drains, which leads to a vast ruined well in the center. This well catches the rainwater and allows for the rapid drainage of the arena, even today.
Abandoned at the end of the fourth century, the amphitheatre came to serve as a quarry. In this manner, the monument was completely stripped of its brick facing.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.