Osijek (ōˈsēyĕk) [key], Ger. Esseg, Hung. Eszék, city (2011 pop. 108,048), in Croatia, on the Drava River. The chief city of the historic region of Slavonia, it is a river port and industrial center. Textiles, leather goods, soap, and agricultural machinery are among its industrial products. Osijek grew around a castle built in 1091 on the site of the Roman colony and fortress of Mursa. It became an early episcopal see and was under Turkish rule from 1526 to 1687. It was later part of Austria-Hungary and passed to Yugoslavia in 1918. Osijek was the scene of fighting between Croats and Serbs in the early 1990s after Croatia declared its independence from Yugoslavia.