The monumental Propylaia were built c. 300 BC, in the north part of the sanctuary of Asklepios. Devotees entered after first acquiring a supply of water for drinking and for purification, from an earlier well (c. 500 BC) to the south of the building, which survives to this day.
The east and west sides of the Propylaia were closed by walls. On each of the façades were hexastyle Ionic colonnades, crowned by an elaborate entablature. On the north and south fronts there were pediments. In the interior of the Propylaia were decorative Corinthian colonnades and a square peristyle space with entablature decorated on the north and south sides with relief rosettes and bucrania.
The Sacred Procession arriving from the Sacred Way halted in this square room, in order for pilgrims to pray before entering the sanctuary. The procession was attended by the archons of the city of Epidavros, about 15 km. away, and the visitors, who were numerous because this took place on the occasion of the “Asklepieia”. This great festival was celebrated every four years and many people were mobilized for its preparation.
The Propylaia were not closed by doors, they had additional passageways on their west and east sides, and a large ramp at the centre to facilitate the movement of chariots in the ceremonial procession. The foundations and the base (crepis) of the monument survive, as well as many architectural members from the fallen superstructure.