The Hosios Loukas Monastery (Saint Lucas Monastery) is built on the western slopes of Helicon below the acropolis of the ancient town of Stiri, near the village Stiri in Boeotia. It is one of the most important monuments of Middle Byzantine art and architecture and is included in the list of World Heritage Sites of UNESCO together with the monasteries of Nea Moni and Daphni. The monastery is dedicated to St. Lucas Stiriotis (29 July 896-7 Φεβρουαρίου 953).
A. The Church of Our Lady (Panagia), the oldest in the complex, is the only one which is known to have been built in mainland Greece around the tenth century. The architectural style of the complex is a four cruciform church with a dome, which distinguishes the architecture faculty of Constantinoupolis. In the nave is added a spacious narthex. To the west of the narthex there is a peculiar type of exonarthex that consists of an open porch with two closed compartment on both ends that protrude from the sides of the nave. The south porch of the apartment was incorporated into the later church, the catholic of the convent. During restoration work under the revetment of the catholic revealed a great mural that once adorned the eastern wall of the southern district of this exonarthex. The unique mural saved from the original decoration of the church of Our Lady recounts the appearance of the Archangel Michael to Joshua before the fall of Jericho. Murals are preserved also at the southern part of the cross and at the “diakonikon”, represented a total of five types of hierarchies, have been dated in the late 12th century.
B. The Cathedral was built to house the relics of the Saint and it is the largest church of the monastery, located south of the church of Our Lady (Panagia).
Belongs to the type of "continental octagonal churches" and even it is considered the standard of all subsequent temples of this type. In octagonal temples, which are essentially cross temples, only the supporting of the dome is octagonal, while the central space below it remains square. The church of St. Luke is characterized from its large dome (diameter approximately 9 m) and correspondingly the extended single square space below him. The weight of the dome is supported by eight heavy pillars bridged to a great height in four large arches between four semi-vaults. From the chapels surrounding the square core is particularly important the northeastern, because there (to the contact point with the northern arm of the cross) is placed the marble reliquary of the saint. It is the part of the Cathedral, which is connected with the Church of Our Lady (Panagia), facilitating the passage of pilgrims in front of the relic and entering to the temple of Virgin Mary. Simultaneously with the cathedral was built the crypt having in floor plan the shape of a four-columned cross temple. In crypt there is the initial tomb of St Luke, located on the north wall, just below the site of the ledger, which placed the reliquary of the saint. Two other tombs in the crypt belong to eminent bishops of the monastery.
Other buildings that have been restored are a) the stable, in which are exhibited frescoes of the 18th century from the church of St. Spyridon, dependency of Saint Luke at the Stiri area, b) the “fotanamma” with its distinctive chimney and c) the bank, which since 1993 operates as a museum and includes architectural elements from various construction phases and findings from the surrounding area.
Hosios Loukas is the largest of the three surviving monasteries of the Middle Byzantine period in Greece. It differs from Daphni Monastery and New Monastery, that is dedicated to a single Saint. The prophecy of the Saint for the recapture of Crete commemorated by the image of Joshua on the outside wall of the church of Our Lady (discovered during the restoration in 1964). Joshua was considered "Fighter of the faith", whose assistance was effective in the wars against Arabs. The Cathedral contains the best preserved mosaics from the period of the Macedonian Renaissance. But all is not over: the original image of Christ Pantocrator in the dome is missing, as also the forms of the archangels, normally fitted between the upper windows.
There is evidence that the monastery was famous throughout Byzantium for the luxury of decoration, which spread over all of its surfaces. Besides the walls, sculpture, gold and silver plates, murals and mosaics (especially striking on concave surfaces), the interior was decorating by pictures, chandeliers, silk curtains and fabrics altars (antimensia). Only a fraction of them survives in place, notably the colored marbles investment and railings of the windows. Despite the losses the Catholic "gives the best impression can be learned anywhere today form the interior of a church in the first centuries after the end of Iconoclasm".
(Translation from Wikipedia by C. Theodorou)