On the northeastern side of Upper City, under the walls, near the Byzantine baths is the church of Pammegistoi Taxiarches, one of the many and important Byzantine museums of Thessaloniki, significantly altered by the showcases and the repairs that have been made through the years.

It was constructed in the second half of the 14th century and was the catholicon of a monastery, whose name is not known. During the period of the Turkish occupation it was converted into a mosque and was called Ιki Serife Mosque, that is mosque with two balconies, because it has the famous minaret with the two balconies, because they symbolized the two Archangels. After the liberation of the city, in 1912, it operated again as a Christian church, they demolished the minaret in 1925 and in 1953 the church was restored. In its initial form it was a small aisleless, wooden-roofed basilica with two levels and a portico Π-shaped in three sides, which on the eastern edge ended in two chapels. Nowadays, only the eastern part of the initial building survives, under the arch of the altar area. After many alterations, on the southern side they have shaped yet another aisle for the creation of a larger interior area, while on the western one there is a closed narthex. Under the elevated floor of the church there is a crypt, which was used as a burial site of the monks, as indicated by the arcosolia, that is the conches that are opened in its walls. Nowadays, it is dedicated to Agioi Theodoroi and is a place of worship.

Externally, the initial masonry of the church is the characteristic of the Byzantine monuments of Thessaloniki, cloisonné with the rich ceramic decoration with dentil courses and small columns, which is preserved on its eastern side. Its interior is decorated with remarkable wall paintings, possibly the work of the famous painter Georgios Kalliergis. From the representations survive the Ascension of Christ and the Pentecost, made in a special way at the two gambles of the church.