The Monastery of the Brigadiers (Taxiarches) location has been identified with the Castle of the Archangel, which is associated with the Accagioli family (a family of bankers from Florence).
The Castle is included in the list of manors of 1377 as Sancto Arcangelo and as the estate of the Great Senescallo (Gran Senescallo), that is, of Niccolo Acciaiuoli. The foundation of the Castle is placed around 1340. Due to the pre-existing Byzantine church, the Latins gave the Castle the name of Archangel Michael. In 1418, the Castle passed into the hands of the Byzantines of the Despotate of Mystras, while in 1460 the area was occupied by the Turks. Although there is no evidence, the complex must have remained in use during the Turkish occupation, probably as a monastery.
The wall of the Castle is built of small rough stones with pieces of bricks. To the east, it is preserved at a great height where two construction phases can be distinguished. To the west, the wall is not preserved, while to the south it is almost destroyed by a square tower to which a two-storey building is adjoined. The tower is not like the usual defensive towers found in castles. It is a remnant of a normal castle. Next to the Castle, on a tall pile of stones, the figure of a lion-vigilant guard of the Castle and the Monastery can be seen.