The Amphiareion at Oropos, sanctuary of the hero Amphiaraos, was greatly famed and frequented by pilgrims who went to seek oracular responses and healing.
The largest building in the sanctuary is a stoa (mid-4th century BC) which served as the enkoimeterion for the patients.
The sanctuary also contained a theatre. The theatre is dated to the 2nd century BCE by inscriptions and the seating area was likely composed of wooden seats on stone supports.
Five marble prohedria (seat of honor at the front of the seating area) were discovered placed around the orchestra.