Mansion Garden and Amphitheater

View looking southwest from the Byzantine Mansion. In the foreground, the planted area was a portion of the "Sunken Garden" of the mansion.

In the excavated square, please note the curved line of ashlar stones that was part of an earlier structure—namely an amphitheater that was constructed in the southern portion of the Hippodrome/Circus during the second century AD. The Amphitheater probably was constructed during the reign of Hadrian (r. 117–138 AD) when the new, Eastern Hippodrome was built, and this one, and the seaside "real estate" was repurposed!

In the distance, the Promontory Palace is visible.

For an example of a Stadium turned into an Amphitheater see this example from Perga.