Located next to Hodegetria in the north-eastern part of the Lower Town in Mystras, the church of Agioi Theodoroi was originally the catholicon and then the burial church of Vrontochi Monastery. It was built in 1290-1295 by Pachomius and Daniel, monks who are mentioned in a verse inscription on the templon architrave . Agioi Theodoroi exhibit the general features of a mainland octagonal church , but three centuries after the type was first employed at Agios Loukas in Phocis, the church displays a series of remarkable innovations. There are no tribunes or narthex , the dome is only supported on columns to the west, and the side compartments have barrel vaults rather than groin vaults . There are chapels in all four corners, the east of which served as a burial place.

Externally, this evolved type of church takes the form of a cuboid building deftly scaled up, thus counterbalancing the aesthetic effect of the massive central dome. Decoration on the side walls is then taken up by characteristic features of the Greek school, such as zones of cloisonné masonry , dogtooth bands , ceramic cups, which initially coexisted with abacus-like friezes , quadrant arches flanking the windows and curved pediments . This special monument was supplemented by a narthex with tower-like corner chapels to the west, and a closed gallery to the north. The interior retains part of the original decoration dating to the late 13th century. The lower surfaces are covered in a series of full-length military saints above a zone imitating marble revetments , while the upper parts are covered with scenes from the Life of the Virgin Mary and the Passion and Resurrection of Christ. The later frescoes in the southeast chapel, which is apparently dedicated to Our Lady of the Life-Giving Spring, may date to around 1400. The figures of two Byzantine nobles are depicted on the north and south walls. In the north-east chapel there is a tomb and depiction of someone called Manuel Palaeologus kneeling and praying in front of the Virgin and Child. According to an inscription, Manuel died in 1423 or 1453.

Surviving traces of the decoration in the north-west narthex chapel depict the miracles of Archangels Michael and Gabriel, to whom it was probably dedicated.