"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus
Kosovo was under Ottoman rule until the First Balkan War in 1912. After the war, Serbia was hoping to annex what is now northern Albania to get access to the Adriatic Sea, but Austria and Italy were opposed to Serbia having a coastline on the Adriatic. Austria apparently wanted Kosovo to be part of Albania. It was because of support from France and Russia that Serbia got Kosovo then (except for a small portion which went to Montenegro, but later went to Serbia when Tito redrew the borders after WWII).