Located in Plaka, the church of St. Aikaterini was built in the mid-11th century. Byzantine experts believe this domed cross-in-square, four-aisled church was dedicated to Saint Theodoros, as indicated by the inscription on the marble column supporting the altar.
This church formerly served parishioners from the Alikokos neighbourhood in Plaka, just opposite the Choragic Monument of Lysicrates, which was later incorporated into the Catholic Capuchin Monastery. Its interior murals were painted in the late 19th century by G.D. Kafetzidakis.