Osios Loukas Monastery stands as one of the most important and well-preserved monuments of Middle Byzantine architecture in Greece. Located on the western slopes of Mount Helicon near the town of Distomo in Boeotia, this UNESCO World Heritage Site lies about 35 kilometers southeast of Delphi and 150 kilometers northwest of Athens. 

The monastery honors Saint Loukas, a 10th-century monk and healer. He settled in the area around 946 AD and built a small church dedicated to St. Barbara. After his death in 953, his followers honored his memory by expanding the complex. As more pilgrims visited the site to pray at his tomb, the community grew. Over time, the monastery became a major center of worship and healing in Central Greece. 

Osios Loukas Monastery includes two main churches. First, the Church of Theotokos, built in the late 10th century, follows a simple cross-in-square plan. Next to it, the larger Katholikon, constructed around 1011 AD, displays the octagonal domed style typical of Middle Byzantine design. These churches connect through a shared narthex. 

Inside, visitors can admire vivid mosaics and frescoes with gold backgrounds, biblical scenes, and portraits of saints. These artworks date back to the 11th century and represent some of the finest examples of Byzantine religious art in Greece. 

Travelers can reach the monastery easily by car from Athens or Delphi. Clear signs guide the way, and a parking area stands near the entrance. The site remains open daily, and entrance fees are low. Discounts apply for students, seniors, and children. Modest clothing is required, and photography inside the churches is not allowed. 

Many travelers choose to combine their visit with other nearby destinations. The archaeological site of Delphi, the mountain village of Arachova, and the Krya Springs in Livadeia offer excellent options for a full day of exploration.