Some of the very few mosaics of the Byzantine dark ages are preserved in the churches of Ayios Demetrios and Ayia Sophia in Thessalonike. Between 629 and 634 Ayios Demetrios was burnt, and upon its ruins a large, five-aisled basilica with transept was raised. Of the new mosaics that adorned the church six have survived, principally depicting Saint Demetrios with the new founders, clerics or children. These are pictures dedicated to the saint by the faithful.
The decoration in the sanctuary of Ayia Sophia consists of crosses and palmettes, typical iconoclastic themes. On the basis of the monograms of the emperor Constantine VI, his mother Irene and bishop Theophilos, it is dated to the period 780-787.