At one time, Kosovo had been the heart of the Serbian Empire, only to be lost to the Ottomans in 1398, according to BBC's timeline. Centuries later, in 1912, Serbia regained control of Kosovo, and by 1946, Kosovo was absorbed into the Yugoslav federation. Around the 1960s, Kosovo began to assert its autonomy, being a majority-Muslim province after centuries of Ottoman rule, in a majority-Christian federation. The Yugoslav federation accepted this autonomy in the 1980s, giving Kosovo a 'de facto self-government'.

But from 1998-99, Kosovo was the site of a bitter and deadly war that killed thousands, largely fought between ethnic Serbs and ethnic Albanians. It was the Federation of Yugoslavia (which included Montenegro and Serbia at the time) against Albanian rebels. In a conflict that spiralled into killings and revenge killings, NATO finally intervened against Yugoslavia, and the Kumanovo Agreement was reached in 1999 to end the war.