Dobojgrad

Dobojgrad guards the Bosna valley in northern Bosnia, where the river descends towards the plains of the Sava. Its fortress, raised above the valley, was a royal stronghold of the Bosnian Kotromanić dynasty and a point of contention between Bosnia and Hungary. The castle was strengthened in 1415, when war brought Hungarian forces into Bosnia and a Bosnian–Ottoman alliance defeated them.

The Ottomans later took the fortress and enlarged its defences. In the early summer of 1490 workers under the master builder Ibrahim added another outer wall and strengthened the stronghold. From its hill, the castle watched over the river corridor between the Bosnian interior and the northern lowlands, remaining a fortified place through the long struggles along the Ottoman frontier.