sentences:  The Banate of Usora had many strong fortresses and cities on its territory, the most famous ones being Doboj (13th century), Srebrenik (1333), Dobor (1387), Glaz (12th century), Soko (14th century), Tešanj (14th century), Modrić (13th century), and Maglaj (15th century).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 Hungarian kings who viewed Banate of Bosnia as vassals to them.Although it was nominally a part of the Hungarian Crown Lands, the Banate of Bosnia was a de facto independent state for most of its existence, including Usora, which when under Bosnia always retained great autonomy.