The Stavropegic Monastery of Vlatadon is located at the north edge of the historic center of Thessaloniki, near the gate to the citadel and south of Acropoleos Street. Though originally consecrated to Christ Pantocrator, it is now dedicated to the Transfiguration. Erected by Theodore Vlatis, a pupil of Gregorios Palamas, Archbishop of Thessaloniki (1351-1371), it is the only monastery in Thessaloniki where worship has continued almost uninterruptedly to the present day.

The catholicon was the prinicipal monastery building. It is a variation of the cross-in-square church with a peristyle . The dome is not entirely supported by pillars , as per usual, but rests on the sanctuary walls and on two pillars on the west side, probably because the remains of an older building were incorporated into the church.

Only the east side of the exterior retains the form of a Byzantine church, since later modifications have significantly altered the other sides. The masonry is clearly visible on the east side, consisting of three courses of stone alternating with pieces of brick. The octagonal dome is also made of brick, with brick half columns at the corners and six windows. During the Ottoman period the peristyle was extended to west and north and a uniform roof was built, followed by a porch to the south, a propylon to the west and a parapet around the porch and propylon.

Inside the church and the south chapel of Saints Peter and Paul are frescoes dated to 1360-1380. The iconographic programme contains the Almighty with hosts of angels and prophets in the dome. Scenes from the Dodecaorton still survive on the intrados of the arches, as well as saints – mainly hermits and monks - in two zones on the walls. Military saints can be seen on the lower parts of the gallery, above which are representations of Christ’s miracles; scenes showing the Baptism and the Three Children in the Fiery Furnace still remain intact in the two small conches of the narthex , as they escaped damage from hammering when new mortar was applied to the walls. Assistance in dating the wall paintings to between 1360 and 1380 is provided by a depiction in the nave and chapel of Grigorios Palamas, who died in 1359. The fact that he is shown among known Church theologians stands as proof of the monastery’s involvement in the Hesychasm movement.

It is worth noting that throughout its history, including the brief period when it was converted into a mosque under Ottoman rule, the catholicon suffered significant damage, mainly because the walls of the older building were poorly incorporated into the catholicon; most recently it suffered considerable strain during the 1978 earthquakes.

Important information on the building’s historical development and construction came to light in the course of a comprehensive conservation and restoration project from 1980 to 1985. Accumulated damage to the catholicon was treated at the same time.