Violence against Serbs during the late Ottoman era
The Principality of Serbia received autonomy from the Ottoman Empire in the early 19th century, but a Serb population remained to the south, outside of the borders of the principality. With the Serbian–Ottoman Wars (1876–1878) and the Congress of Berlin, the Serbian borders were expanded.
Source: Wikipedia — Violence against Serbs during the late Ottoman era (CC BY-SA 4.0)