ancient fortified plateau west of Syracuse, Sicily, which was enclosed with walls some 12 miles (19 km) long by the tyrant Dionysius I (c. 430–367 BC). The southern wall, of which considerable remains exist, was probably often restored. Epipolae narrows to a ridge about 180 feet (55 m) wide at one point, and there stand the ruins of the most imposing fortress to survive from the Greek period. Behind the castle is the well-guarded main entrance to the plateau. There are minor entrances on the northern and southern sides. On the northern side of Epipolae the cliffs are relatively abrupt.