The Balkan is always complicated. What was Yugoslavia during the cold war up until around 1990 - a conglomerate of several states - has today fallen apart into Slovenia, Croatia, Bosnia-Herzogovina, Macedonia and Yugoslavia (which consists of former Yugoslavic 'states' Serbia and Montenegro), each of them sovereign states. However, the state Macedonia is not identical with the (ethnic) area of Macedonia, as parts of historical Macedonia ended up in Greece and Bulgaria, after the dissolution of the Turkish-Osmanic Empire in the 1920's. Thus Macedonia wanted to and did secede from the Yugoslavia that emerged after cold war/communist Yugoslavia dissolved, but they have issues with Greece as well. I think they're pretty cool with Bulgaria though. Complicated, eh ?