Telesterion

A great hall in Eleusis, Telesterion was one of the primary centers of the Eleusinian Mysteries. Devoted to Demeter and Persephone, these initiation ceremonies were the most sacred and ancient of all the religious rites celebrated in Greece. At some point in the 5th century BC, Iktinos, the great architect of the Parthenon, built the Telesterion big enough to hold thousands of people. In about 318 BC, Philon added a portico with twelve Doric columns.