It was built in two stages, first about 130 AD then expanded around 165 AD. The first amphitheatre was built when the hillside was terraced. The arena floor was laid out and flattened. This first structure had 24 rows of seats built mostly of wood rising up the hillside. The stairs, the wall around the arena floor, the upper walls, and the entrances were built of stone. The outer walls of the amphitheatre measured and the arena floor was . The first amphitheatre could hold about 9,000 people.