A small chapel in the form of a timber-roofed, triple-aisled basilica dedicated to Saint Euthymios was erected in the 11th century near the south-eastern corner of the basilica of Ayios Demetrios.
The interior was decorated with wall-paintings in 1303 at the expense of the nobleman Michael Glavas Tarchaniotis and his wife Maria. Michael Tarchaniotis was 'protostrator' (general commander) of the Byzantine army in the reign of Andronikos II Palaeologos, and founder of the important Pammakaristos Monastery in Constantinople, which accommodated the Patriarchate for a time in the 16th century.
It is clear that Michael was a man of some consequence, as was the eminent painter who undertook the decoration of Ayios Euthymios. The artist produced one of the most significant works executed during the Palaeologan renaissance; in many respects it resembles the paintings in the Protaton church on Mount Athos.