Andromonastiro (the male monastery) is located southeast of the village of Petralona, not far from ancient Messene, in a forested valley of great natural beauty. Tradition has it that it was founded by emperor Andronikos II Palaiologos (1282-1328). Nowadays it is a dependent of the neighbouring monastery of Voulkano. The monastic complex has a roughly square ground plan and comprises buildings of different dates and various uses.

The main church rises to its southeast, dedicated to Metamorfosi Sotiros (Transfiguration of Christ), built over a natural freshwater spring. The church is a large-sized, domed semi-composite, four-columned cross-in-square type, tentatively dated to the early 13th cent. AD. The church’s present form was shaped by adding an outer narthex and two chapels along its northern and southern sides, possibly at the beginning of the 17th cent. The wall paintings are fragmentarily preserved; three main layers have been recognized that date to the 13th, 17th and 18th centuries. The monastery also comprises the trapeza (refectory) to the north and the adjoining tower, the magipeion (bakery) and a two-storey wing that incorporates the main entrance. To the west there is one more two-storey wing of cells, with stables and a wine press on the ground floor and monk cells and the synodikon (reception room) on the forts floor. A three-storey tower rises at the south end of the west wing; it has been identified as the igoumeneion (the abbot’s quarters). In all, the monastery has six or seven different building phases. The tower was probably built in the first phase and was gradually altered, to take its final form in the 17th century.