Yugoslav Wars
The Kingdom of Yugoslavia was stared in 1918 after World War 1 when Austria-Hungary, led by Charles I of Austria, collapsed.  In 1918, The Austro-Hungarian Empire split into Austria, Hungary, Czechoslovakia, Romania and Yugoslavia.  In 1941, Nazi Germany invaded Yugoslavia during World War 2.  In 1944, both Tito and Stalin pushed the Nazis out of Belgrade with the help of Bulgaria.  In 1948, Josip Broz Tito and Joseph Stalin broke up their friendship. This lasted until the death of Stalin in 1953.  When the invading Warsaw Pact powers ended the Prague Spring in 1968, Romania,Yugoslavia and Albania supported the Czechoslovaks led by Alexander Dubček against the USSR led by Leonid Brezhnev.