Hosios Loukas (monastery) built
901 CE.
Shown on the map at 38.395°, 22.746°.
Hosios Loukas (Greek: Ὅσιος Λουκᾶς) is a historic walled monastery situated near the town of Distomo, in Boeotia, Greece. Founded in the mid-10th century, the monastery is one of the most important monuments of Middle Byzantine architecture and art, and has been listed on UNESCO's World Heritage Sites since 1990, along with the monasteries of Nea Moni and Daphnion.
Text from the Wikipedia article Hosios Loukas, licensed CC BY-SA 4.0.