Τhe Monastery of Kaisariani is dedicated to the Virgin Mary. It lies on the western, wooded slope of Mount Hymettus, about two kilometers from the Municipality of Kaisariani. The monastery is referred to as Kaisariani in a letter written by Michael Choniatis in 1200; in 1208, having passed into the hands of Catholic monks, Pope Innocent III refers to it as Santa Syriani.

The monastery answered directly to the Patriarchate of Constantinople and had secured various privileges and tax exemptions, which led to economic prosperity in the Byzantine period. This status was maintained during both the Frankish and Ottoman periods, and is indicative of the great power and influence wielded by the monastery’s abbots. In 1833 it was dissolved by decree of the regent’s council under King Otto.

The first centre of Christianity in the area was located on a hill to the southwest, known as “the Cemetery of the Fathers”. The remains of an early Christian basilica dating to the 5^th-6th century are still to be seen at the site, where another church was built in the 10th century. Abutting this to the south was the Catholic church of St. Mark, built under Frankish rule and hence known as Frankomonastiro. To the west lies a 17^th century church dedicated to Archangels Michael and Gabriel.

The monastic community was transferred to its safer present-day location in the 11^th century. Of the mid Byzantine buildings only the catholicon and the baths still survive, the latter being one of the few monastic bath houses preserved in Greece. The remaining structures (refectory, kitchen, cells) are of a later date. The cells lie on the south side of the enclosure wall; archaeological excavations have revealed that they were founded on the ruins of Byzantine cells. The main wing is now a two-storey building, standing independent of a three-storey edifice known as the Benizelos Tower.

The church is of the semi-composite four column cross-in-square type , built of the cloisonné masonry typically found in Greece. The exterior decoration is austere: though dogtooth courses and cornices run around the dome , there are no kufic ornaments or other decorative brick elements. The dome is illuminated by eight single-lobed windows surrounded by double brick arches. One characteristic feature is the outstandingly beautiful large stone arch in the north arm of the church, built of finely hewn masonry. The apse has a large biforate window with a plate above it.

On the interior, the columns supporting the dome are from earlier buildings, while the restored marble templon is contemporary with the church. There are two different views as to when the catholicon was erected: one places it in the late 11th century and the other later, in the 12th century. The wall paintings in the nave date to the early 18th century and are the work of an accomplished academy-trained artist.

The tripartite domed narthex and the chapel of Agios Antonios to the south are later additions. The former was erected in the 17th century, and bears wall paintings dated 1682 by the Peloponnesian painter Ioannis Ipatis. The murals in the Chapel of Agios Antonios are of the same period.