Agios Demetrios (Metropolis) , was probably founded by the Bishop Eugenios around 1270 and was renovated in 1291, by the Bishop Nikiforos Moschopoulos and his brother Aaron. It took its final form in the 15th century with the works of Bishop Matheos. It is considered the oldest church in Mystras, cathedral of the city and seat of the Diocese of Lacedaemonia until the first years after the liberation of Greece from the Turks. The church in its current form belongs to the so-called "mixed type of Mystras", which combines the three-aisled basilica on the ground floor and the five-domed cross-in-square church in the upper room, with three three-sided arches to the east.
According to tradition, the last emperor of Byzantium, Constantine XI Palaiologos, was crowned here in 1449. The sculptural decoration of the church has a large variety in terms of style and season. Exceptional samples of Byzantine and later art include the built iconostasis, which took its current form probably in the 18th century, the two shrines with relief designs, the architrave of the time of Bishop Mathaios, with designs carved in porous stone and the parapets in the frieze of the upper room.
The embossed double-headed eagle of the Palaeologos family on the floor of Agiod Demetrios, under the dome, is truly remarkable. The exceptional frescoes of the church (last quarter of the 13th-beginning of the 14th century) have various styles and were mainly date to the period of Bishop Nikiforos. The complex of the Metropolis is completed by buildings that were added later: the tower-shaped bell tower (in the southeast corner), the portico with the pillars and the arches on the west facade, a second portico on the north side, with an excellent view to the valley of Evrotas, as well as the beautiful north courtyard with the arches and two-story buildings, works of Bishop Ananias, who was slaughtered by the Ottomans in 1760. The place where he martyred is just outside of the Metropolis and has been fenced.