Szigetvár (sĭˈgĕtvär) [key], town (1991 est. pop. 12,280), SW Hungary. A medieval fortress, it was defended in 1566 by Nicholas Zrinyi against the Ottoman sultan Sulayman I, who died during the siege. Zrinyi was killed during a sortie, and the fortress eventually fell to the Turks. A mosque originally built for Sultan Sulayman I is now a church.