The 1600s were a turbulent time in the Balkans. The small Principality of Montenegro was fighting for survival against the mighty Ottoman Empire. Threatened by Ottoman raiders, many Orthodox Christians took to the mountains.
Ostrog monastery was carved out of a vertical mountainside of of Ostroška Greda. Founded by Vasilije, the Bishop of Herzegovina and later known as St. Vasilije of Ostrog, his body is enshrined in a reliquary kept within the cool dark walls of the cave-church. Word spread quickly of the supposed miraculous healing powers of his mortal remains, and the monastery become a center of pilgrimage not only for Orthodox Christians but Catholics and Muslims as well.
The tradition of pilgrimage continues to this day, with Ostrog still receiving visitors from far and wide of varying faiths, with an especially large celebration taking place on Pentecost. Much of the present look of the cave monastery complex dates from a 1923-1926 renovation after a fire. The monastery was seriously damaged in the blaze, but luckily two of the original cave chapels were spared and remain in their original condition.
St. Vasilije of Ostrog is still there as well, though, over the years he has lost some of his "original condition."