Sometime in the first half of the third century, an oval-shaped building (c. 42m by 38m) was constructed in the open space to the east of the Palazzo Imperiale. All that remains now are the foundations which reveal that the building’s superstructure was composed of two parallel walls spaced three meters apart with an additional façade wall only present on the western half of the building. The structure has the characteristic form of an amphitheatre, though is considerably smaller in size. Its entrance was located on the west side through the façade wall which was accessed via a row of rooms of contemporary date on the Palazzo‘s east side. The rooms, including a three-seater latrine, were lavishly decorated with marble and painted stucco and fronted onto a garden to the west. The amphitheatre-shaped structure was systematically demolished sometime in the early fourth or fifth century.
Video below: A virtual reality reconstruction which interprets the evidence for the amphitheatre-shaped building.