Radoslav Čelnik

Radoslav Čelnik (Serbian Cyrillic: Радослав Челник, Hungarian: Cselnik Radoszláv; fl. 1526–1532), known as Vojvoda Rajko (војвода Рајко), was a Serb general (vojvoda) in the army of Jovan Nenad, the titular Serbian Emperor who held present-day Vojvodina, who after the death of Jovan Nenad (1527) took part of the army from Bačka to Syrmia and acceded into Ottoman service. Radoslav then ruled over Syrmia as "Duke of Syrmia (Srem)", initially as an Ottoman vassal (1527–1530) and then as a Habsburg vassal (1530–1532), until the region was conquered by the Ottomans. His residence and capital was in Slankamen (sr).