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.