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The medieval fortified town of Greben is located in Krupa na Vrbasu, 25km south of Banja Luka. The town is mentioned for the first time in sources from 1192 , and then in 1322 and in 1346 during the times when a certain Nikola was ruling the town. In the 14th century, Greben was owned by feudal lords Hrvatinići, who were the masters of Donji Kraj, as evidenced by charters signed in 1374 and 1375. The town was destroyed during the fall of the Banovina of Jajce under the Ottoman rule 1527-1528, and it is also mentioned in Ottoman sources from 1562, in the area of Jajce nahiyah, under the names Greben and Vrh Krupa. It appears that the city was abandoned in the period of Ottoman rule. It is in ruins today. Only the tower next to Vrbas and part of the walls descending towards the river canyon are slightly better preserved.
Krupa na Vrbasu, Bosnia and Herzegovina