Kukanj was known as the «summer residence» of the Kosaca family. In Kukanj, Sandalj Hranic issued a certificate to people of Dubrovnik in 1423. The 1444 charter of the Aragon-Neapolitan king Alfonse V mentions Kukanj in Breznica, and so do the charters of Friedrich III.
The upper part of the town, which was smaller, seems to have been separated from the lower one by a natural dry moat. From the remains of their foundations, we can conclude that several different buildings existed within the fortification, and that one of three existing holes was probably a water cistern. Bellow the fortification, towards the west, an old graveyard has been found on the hill ridge. Even today, in maps we can find the locality of Podkukanj, which has kept the name of its suburb. However, the suburb remains have not been found.