Frontier fortresses Fortification architecture on the Croatian and Slavonian Military Frontier Major fortresses Gradec (Zagreb) Episcopal Fortress Kaptol (Zagreb) Senj Nehaj Fortress (Senj) Đurđevac Ivanić Grad Koprivnica Križevci Varaždin Konjščina Minor fortresses Glogovnica Brinje (Sokolac) Trsat (Novi) Vinodol Bela Bisag Božjakovina Čanjevo Gorica Gradac Kostajnica Legrad Ludbreg Rasinja Remetinec Veliki Kalnik Varaždinske Toplice