The exact date of construction of the Coliseum is not known. Most likely it was built between 230 and 238 years by Emperor Gordian. Gordian was the owner of these lands. The long axis of the Coliseum has a length of 450 feet, short - 370 feet. Dimensions oval arena (its axes) - 197 and 122 feet. The height of the walls reached 90 feet. The Colosseum was designed for around an 30000 spectators. The facility was built of very soft sandstone mined from the quarries on the coast, about 20 miles from El Jem. In the Coliseum were different perceptions - and the struggle of people with pets and animals together. Stories about this brought us mosaics found here. Now the mosaic is stored in the Bardo Museum and the city of El Jem.
In subsequent centuries, the Colosseum was used several times as a fortress. Berber princess Kaena (Kahena) is fought against Arab armies. (By this time, is a legend that the Colosseum is linked underground passage to the sea, although most likely an underground passage did exist, but does not lead to the sea behind a lot of miles, and to the nearby stables). Like a fortress used arena and in the eighth century and even in 1695, when the local population rebelled against the Bey. And in recent times, the troops fired at the Coliseum without thinking of the guns to smoke out the rebels. In 1850, during a new excitement, firing repeated. Also served as a monument and quarries for new construction. All this led to the fact that about half of the buildings had been destroyed almost completely.
Info from: http://www.russiancity.ru/tunis/tunis7.htm