 The trend continued in Old Montenegro after 1711 with the extermination of converts to Islam ("istraga poturica").Another contributing factor that spurred migration to Sandžak from the Old Montenegro was the fact that the old Orthodox population of Sandžak moved towards Serbia and Habsburg Monarchy (Vojvodina) in two waves, first after 1687, and then, after 1740, basically leaving Sandžak depopulated.The advance of increasingly stronger ethnic Montenegrins caused additional resettlements out of Montenegro proper in 1858 and 1878, when, upon the Treaty of Berlin, Montenegro was recognized as an independent state.