After the Serbian–Ottoman War (1876–78) and the suppressed Kumanovo Uprising, the Ottomans retaliated against the Serb population in the Ottoman Empire. Because of the terror against the unprotected rayah (lower class, Christians), many left for the mountains, fled across the border into Serbia, from where they raided their home regions in order to revenge the atrocities carried out by the Ottomans. After the war, the Serbian military government sent armament and aid to rebels in Kosovo and Macedonia. Christian rebel bands were formed all over the region. Many of those bands, privately organized and aided by the government, were established in Serbia and crossed into Ottoman territory.