Extensions and additions have been made to the church and the only testamonies to its age are the Athenian-type dome and parts of the north and south walls which are built of cloisonne masonry (two colored bricks).
The Church is a cross-in-square type with dome. Incorporated into its facade are two terracotta plaques with ornaments and letters imatating old Arabic script. Their striking similarity to the plaques in the church of St. Theodore helps archeologists to to date Aghoi Assomati to around 1065. You can't miss this church as you walk from Constitution Sq. to Monastiraki Sq. down Ermou (Hermes) Street in central Athens.