They regularly attacked their western neighbour, the Hungarian vassal Stefan Dragutin's Syrmian Kingdom, in Mačva, an area previously under the sovereignty of Elizabeth of Hungary.
In roughly 1291 and with the help of Milutin, Stefan Dragutin expanded his territory by annexing regions of Braničevo and Kučevo, whose Bulgarian rulers Darman and Kudelin recently became independent from the Kingdom of Hungary.