Situated on the wider archaeological site of Plaošnik, the site has been an important religious center since early Christian times, if not before. It is the site of the first university in Europe, opened in the 10th century and is the place where the Cyrillic alphabet was created. The church you see is largely a reconstruction of the church St Clement built when he came here and opened the university. The original portions are the church are easily distinguished from the reconstructed portions. Inside, some original tunnels are visible via plexi-glass. When St Clement established the church, just the small round chapel that today serves as the altar existed. Because of the large influx of worshipers that followed him, he enlarged the church by building the central part of the church and turning the existing church into an altar chapel. He dedicated the church to St Pantaleon (also spelled Panteleimon), the protector of health. The closed porch and the bell tower were added later in the 13th century. Before St. Clement died, he dug his own grave inside the church. During early Ottoman rule, the Turks tore the church down after a rebellion. It still attracted a large number of worshipers and pilgrims, so they built a mosque above it which stands only in ruins today.