Hosios Loukas, Byzantine monastery in Distomo-Arachova-Antikyra Municipality, Greece

Hosios Loukas is a walled monastery whose two churches adjoin at the tomb of Saint Luke. The older, the Panagia, is a cross-in-square church of stone, brick and marble with pseudo-Kufic patterns; the larger Katholikon, dated to 1011–12, is the earliest surviving domed-octagon church, its hemispherical dome set on squinches above eight piers. The lower facade has three arched openings with wooden doors and windows, and a rough stone wall to the left carries a white sign.

Luke of Steiris, born in 896 at Kastri in Phocis, settled on this slope of Mount Steiri in 946–947 and died there on 7 February 953; a general named Krenites paid for the church of Hagia Barbara during his lifetime. Monks built a cross-shaped structure over his grave in 955, and the translation of the relics is placed in 1011, when the Katholikon was raised under the abbot Philotheos. In 1206 the papal legate Benedict of Porto handed the monastery to the canons of the Holy Sepulchre.

The monastery is dedicated to Luke of Steiris, a hermit who died on 7 February 953 and whose tomb stands at the junction of the two churches. Pilgrims slept beside it hoping for healing from the myron the relics were said to exude, and mosaics near the tomb show Luke with hegumen Philotheos holding a model of the church.

The site is accessible from outside, and visitors can explore both churches freely, noticing the differences in size and decoration between the spaces. Appropriate dress is recommended since this is a sacred space.

The crypt, reached by a stairwell on the south side, has nine groin-vaulted bays and forty medallion portraits of apostles, martyrs and abbots, including Philotheos. Its frescoes were cleaned in the 1960s after centuries under dust; most were painted after 1048, when the abbot Theodore Leobachus died.