Hosios Loukas (Greek: Ὅσιος Λουκᾶς) is an historic walled monastery situated near the town of Distomo, in Boeotia, Greece. It is one of the most important monuments of Middle Byzantine architecture and art, and has been listed on UNESCO's World Heritage Sites, along with the monasteries of Nea Moni and Daphnion.
The main shrine of the monastery is the tomb of St. Lukas, originally situated in the vault, but later placed at the juncture of the two churches. The monastery derived its wealth (including funds required for construction) from the fact that the relics of St. Lukas were said to have exuded myron, a sort of perfumed oil which produced healing miracles. Pilgrims hoping for miraculous help were encouraged to sleep by the side of the tomb in order to be healed by incubation. The mosaics around the tomb represent not only St. Lukas himself, but also hegumen Philotheos offering a likeness of the newly-built church to the saint.
The Church of the Theotokos adjoins a larger cathedral church, or Katholikon, tentatively dated to 1011-12. The Katholikon is the earliest extant domed-octagon church, with eight piers arranged around the perimeter of the naos (nave). The hemispherical dome (without a drum) rests upon four squinches which make a transition from the octagonal base under the dome to the square defined by the walls below. The main cube of the church is surrounded by galleries and chapels on all four sides.
There is evidence that the monastery was reputed all over Byzantium for its lavish decoration, liberally applied to all surfaces. Apart from revetment, carving, gold and silver plate, murals, and mosaics (especially imposing on curving surfaces), the interior featured a choice assortment of icons, chandeliers, silk curtains, and altar cloths. Only a fraction of these items are still in situ, most notably colored marble facings and window grilles. Notwithstanding the losses, the Katholikon "gives the best impression available anywhere today of the character of a church interior in the first centuries after the end of Iconoclasm".
6. Efthalia Rentetzi, Mosaici del monastero di Hosios Lukas in Focide e della basilica marciana: parentele stilistiche, in Arte - Documento, n. 16, 2002, pp 66-71, ISSNT IT 1121-0524