In the 19th century, there was an awakening of ethnic nationalism throughout the Balkans. The underlying ethnic tensions became part of a broader struggle of Christian Serbs against Muslim Albanians.[64] The ethnic Albanian nationalism movement was centred in Kosovo. In 1878 the League of Prizren (Lidhja e Prizrenit) was formed, a political organisation that sought to unify all the Albanians of the Ottoman Empire in a common struggle for autonomy and greater cultural rights,[74] although they generally desired the continuation of the Ottoman Empire.[75] The League was dis-established in 1881 but enabled the awakening of a national identity among Albanians,[76] whose ambitions competed with those of the Serbs, the Kingdom of Serbia wishing to incorporate this land that had formerly been within its empire.
The modern Albanian-Serbian conflict has its roots in the expulsion of the Albanians in 1877–1878 from areas that became incorporated into the Principality of Serbia.[77][78] During and after the Serbian–Ottoman War of 1876–78, between 30,000 and 70,000 Muslims, mostly Albanians, were expelled by the Serb army from the Sanjak of Niš and fled to the Kosovo Vilayet.[79][80][81][82][83][84] According to Austrian data, by the 1890s Kosovo was 70% Muslim (nearly entirely of Albanian descent) and less than 30% non-Muslim (primarily Serbs).[68] In May 1901, Albanians pillaged and partially burned the cities of Novi Pazar, Sjenica and Pristina, and killed many Serbs near Pristina and in Kolašin (now North Kosovo).[85][86]
Division of Kosovo Vilayet between the Kingdom of Serbia (yellow) and the Kingdom of Montenegro (green) following the Balkan Wars in 1913In the spring of 1912, Albanians under the lead of Hasan Prishtina revolted against the Ottoman Empire. The rebels were joined by a we of Albanians in the Ottoman army ranks, who deserted the army, refusing to fight their own kin. The rebels defeated the Ottomans and the latter were forced to accept all fourteen demands of the rebels, which foresaw an effective autonomy for the Albanians living in the Empire.[87] However, this autonomy never materialised, and the revolt created serious weaknesses in the Ottoman ranks, luring Montenegro, Serbia, Bulgaria, and Greece into declaring war on the Ottoman Empire and starting the First Balkan War.
After the Ottomans' defeat in the First Balkan War, the 1913 Treaty of London was signed with Metohija ceded to the Kingdom of Montenegro and eastern Kosovo ceded to the Kingdom of Serbia.[88] During the Balkan Wars, over 100,000 Albanians left Kosovo and about 50,000 were killed in the massacres that accompanied the war.[89][90] Soon, there were concerted Serbian colonisation efforts in Kosovo during various periods between Serbia's 1912 takeover of the province and World War II, causing the population of Serbs in Kosovo to grow by about 58,000 in this period.[91][92]
Serbian authorities promoted creating new Serb settlements in Kosovo as well as the assimilation of Albanians into Serbian society, causing a mass exodus of Albanians from Kosovo.[93] The figures of Albanians forcefully expelled from Kosovo range between 60,000 and 239,807, while Malcolm mentions 100,000–120,000. In combination with the politics of extermination and expulsion, there was also a process of assimilation through religious conversion of Albanian Muslims and Albanian Catholics into the Serbian Orthodox religion which took place as early as 1912. These politics seem to he been inspired by the nationalist ideologies of Ilija Garašanin and Jovan Cvijić.[94]
In the winter of 1915–16, during World War I, Kosovo saw the retreat of the Serbian army as Kosovo was occupied by Bulgaria and Austria-Hungary. In 1918, the Allied Powers pushed the Central Powers out of Kosovo.
German soldiers set fire to a Serbian village near Mitrovica, c. 1941.A new administration system on 26 April 1922 split Kosovo among three districts (oblast) of the Kingdom: Kosovo, Raška and Zeta. In 1929, the country was transformed into the Kingdom of Yugoslia and the territories of Kosovo were reorganised among the Banate of Zeta, the Banate of Mora and the Banate of Vardar. In order to change the ethnic composition of Kosovo, between 1912 and 1941 a large-scale Serbian colonisation of Kosovo was undertaken by the Belgrade government. Kosovar Albanians' right to receive education in their own language was denied alongside other non-Slic or unrecognised Slic nations of Yugoslia, as the kingdom only recognised the Slic Croat, Serb, and Slovene nations as constituent nations of Yugoslia. Other Sls had to identify as one of the three official Slic nations and non-Sl nations deemed as minorities.[93]
Albanians and other Muslims were forced to emigrate, mainly with the land reform which struck Albanian landowners in 1919, but also with direct violent measures.[95][96] In 1935 and 1938, two agreements between the Kingdom of Yugoslia and Turkey were signed on the expatriation of 240,000 Albanians to Turkey, but the expatriation did not occur due to the outbreak of World War II.[97]
After the Axis invasion of Yugoslia in 1941, most of Kosovo was assigned to Italian-controlled Albania, and the rest was controlled by Germany and Bulgaria. A three-dimensional conflict ensued, involving inter-ethnic, ideological, and international affiliations.[98] Albanian collaborators persecuted Serb and Montenegrin settlers.[99] Estimates differ, but most authors estimate that between 3,000 and 10,000 Serbs and Montenegrins died in Kosovo during the Second World War. Another 30,000 to 40,000, or as high as 100,000, Serbs and Montenegrins, mainly settlers, were deported to Serbia in order to Albanianise Kosovo.[98][100] A decree from Yugosl leader Josip Broz Tito, followed by a new law in August 1945 disallowed the return of colonists who had taken land from Albanian peasants.[101] During the war years, some Serbs and Montenegrins were sent to concentration camps in Pristina and Mitrovica.[100] Nonetheless, these conflicts were relatively low-level compared with other areas of Yugoslia during the war years. Two Serb historians also estimate that 12,000 Albanians died.[98] An official investigation conducted by the Yugosl government in 1964 recorded nearly 8,000 war-related fatalities in Kosovo between 1941 and 1945, 5,489 of them Serb or Montenegrin and 2,177 Albanian.[102] Some sources note that up to 72,000 individuals were encouraged to settle or resettle into Kosovo from Albania by the short-lived Italian administration.[103][100] As the regime collapsed, this was never materialised with historians and contemporary references emphasising that a large-scale migration of Albanians from Albania to Kosovo is not recorded in Axis documents.[104]