According to the dubious[1] semi-mythical late 13th century Chronicle of the Priest of Duklja, a Magyar leader named Kisa (Serbian: Kiš) led an invasion into Bosnia, where he was decisively defeated by certain Ciaslavus somewhere on the Drina near a place called Civelino.

[2][3] Kisa's widow requested from the Magyar chief to give her another army to avenge his death.

In the night, the Magyars attacked the Serbs, captured Ciaslavus and all of his male relatives.

Seemingly the region of Syrmia wasn't conquered as the mythical successor Belo fought there at the battle of Bellina and concluded peace with the Hungarians.

[8] However, the account could be just a fantasy,[3] and is chronologically unrelated to the time period of DAI's Časlav, dated according to the source in the beginning of the 9th century,[9][10] meanwhile Bosnia in the mid-10th century would have been ruled by Croatian ban Krešimir (usually identified with Michael Krešimir II) and his son Stjepan (identified with Stephen Držislav), without any Hungarian-Serbian War taking place in the 950/960s.