The Mardaki monastery is located on Mt. Taygetus, near Nedousa (Megali Anastasova). According to a founder’s inscription on the western wall of the main church the stavropegial monastery was founded in 1635 by Theodoros Chandrinos, who is depicted as a monk in the narthex. The monastery was flourishing until the early 19th century; its inaccessibility, on a naturally protected location, explains why it was used by the Filiki Etairia (Society of Friends) and Papaflessas as a stronghold prior to the Greek revolution. The monastery, now in ruins, suffered extensive damage in the 1986 earthquake. The katholikon was restored in 1993-1995.

The enclosure has a triangular shape, with the katholikon at the centre and the various other buildings arranged in multiple levels, due to the sloping terrain, from south to north. The katholikon, dedicated to the Assumption of Mary, is a domed free cross with a narthex. Its interior is decorated throughout, with wall-paintings of the early 17th century by the famous workshop of Demetrios and Georgios Kakkavas of Nauplion. The wood-carved templon dates to 1714, according to the surviving inscription.