The Church of the Transfiguration of the Savior is a complex, four-columned, cross-in-square church dated to the first half of the 11th c., located on Kydathineon pedestrian street in the historic district of Plaka, the old Alikokkou neighborhood of Athens. The church has been renovated several times. It belonged to the type of the cross-in-church, with a dome that is supported by four columns. On its eastern side three semi-circular tall arches are shaped. The initial Byzantine core of the church has been altered today and survives only on the eastern side and at the dome. The first damages were probably made during the Greek Revolution, while large scale unfortunate interventions were made in the period 1847-1855, while the monument had been given to the Russian community of Athens. The Russians, in order to accommodate their needs for worship, expanded the building, adding oblong areas on the northern, southern and western side. Later, in 1908, they added a spacious area on the west and the church took the shape of a three-aisle basilica. The western area was expanded more in the year 1917 and then two bell towers were added. The church’s masonry, as it survives on the eastern side, is a simple cloisonné one. The dome is of the “Athenian” type, octagonal with marble columns on the corners and lobed windows. At the interior of the church, the surviving wall paintings are post-Byzantine ones, from the 18th and the 19th c., and the marble screen is a work that was carried out in the 20th c. At the small courtyard in front of the church a marble fountain of the 17th c. survives as well as scattered ancient architectural members.
Also in the small courtyard of the church, bronze busts of the former President of the Greek Republic, philosopher Constantinos Tsatsos, by renowned sculptor Yannis Pappas, and that of his wife Ioanna Simeonides Tsatsos, by sculptor Nikolas, have been placed. The Tsatsos couple used to live less than a block away, on 9 Kydathineon Street.