The region of Usora was a semi-independent banate in medieval Bosnia. It took its name from the river Usora. Its territory stretched roughly from the area of Kulaši and Prnjavor to its west, to Srebrenik and Lukavac to its east, the river Sava to its north and Žepče to its south. The Banate of Usora had many strong fortresses and cities on its territory, the most famous ones being Doboj (12/13th ct.), Srebrenik (1333), Dobor (1387), Glaz (12th ct.), Soko (14th ct.), Tesanj (14th ct.), Modric (14th ct.), and Maglaj (15th ct.). Also, due to its geographical location (Pannonian plateau) as the northernmost Bosnian land and its richness, Usora was, more often than not, a most common battleground between the Bosnian kingdom and the Hungarian empire. The most famous battles include Battle of Srebrenik (1363), Battle of Dobor (1394 & 1408), and Battle of Doboj (1415). Several times this duchy/banate had been separated from the rest of Bosnian kingdom (and attached to Hungary, banate of Slavonia) temporarily, only to be reunited once again.