In the 10th century, the
Tsar Samuil of Bulgaria built the fortress and church ofSt. Achilliuson an island called Agios
Achillios in the Small Prespa Lake, on the Greek side of the border. The
biggest island in the Great Prespa Lake, on Macedonia's side, is calledGolem Grad("Large Town"), and Snake
Island (Zmiski Ostrov). The other island
