 Complete the following phrase:  The four leading Dahije, Kučuk Alija, Aganlija, Mula Jusuf and Mehmed-aga Fočić, captured Hadži Mustafa Pasha, the Vizier of Belgrade, in October 1801 and killed him on 15 December 1801 in the Belgrade Fortress. This resulted in the sanjak being ruled by these renegade janissaries independently from the Ottoman government, in defiance to the Sultan. The janissaries imposed a system of arbitrary abuse that was unmatched by anything similar in the entire history of Ottoman misrule in the Balkans. The leaders divided the sanjak into pashaluks. The tyranny endured by the Serbs caused them to send a petition to the Sultan, which the dahije learnt of. The dahije started to fear that the Sultan would make use of the Serbs to oust them. To forestall this they decided to execute leading Serbs throughout the sanjak, in the event known as the 