The Early Christian church, whose eastern part still stands to roof height, was built almost entirely from spolia, including inscribed blocks, from the temple of Delian Apollo as well as from other monuments and dedications at the ancient site. Only parts of the entablature and the upper wall of the colonnade, supported at its eastern end by a pier, are visible today in situ. According to an inscription—now lost—carved on a pier capital, construction was supervised by the oikonomos Eugenios.