19th and early 20th centuries
The Macedonian question
In the late nineteenth and early twentieth centuries, the "Macedonian question" was a major problem for European diplomats. Bulgarian territorial claims on Ottoman Turkish-held Macedonia were based on ethnic and linguistic arguments, while Greece appealed to classical history.
Following Russia's military victory over the Turkish Empire, the 1878 Treaty of San Stefano created a "Greater Bulgaria" which included most of "Greater" Macedonia as well as much of modern Albania. The other great powers overturned this treaty, leaving Macedonia under Ottoman rule for another thirty-five years, during which time Serbia and Greece also made claims on its territory.
In 1912, Greece, Serbia, Bulgaria, and Montenegro pooled their military resources and launched the First Balkan War, during which they defeated Ottoman forces on every front.
Afterwards, Bulgaria asked that Serbia transfer territory to it, as the alliance had agreed. Serbia, however, refused and kept the area around Ohrid, Bitola, and Skopje as compensation for the Albanian territory it had been forced to give up. This resulted from decisions made by the six Great Powers of the time (Great Britain, France, Germany, Austria-Hungary, Russia and Italy) at the London Conference of 1912-1913, which included granting independence to Albania.
A year later, Bulgaria, dissatisfied with what it had gotten out of the war, launched the Second Balkan War against its former allies. The Treaty of Bucharest (1913) divided Macedonia among Greece, Serbia, and Bulgaria. Today, Macedonia consists of the area taken by Serbia.
World War II
The struggle over Macedonia drove Balkan alliances in World War II, as it had before and during World War I. Bulgaria allied itself to Germany both times in return for the promise of Macedonian territory.
Bulgaria occupied Macedonia from 1941 to 1944. Bulgarian forces deported Macedonia's Jews to Nazi death camps in 1943, although Bulgarian authorities refused to deport Bulgarian Jews from Bulgaria itself. (A museum dedicated to the Jewish victims of Nazism opened in Skopje in 2011.)
After the war, Macedonia received the status of a constituent republic in the new Yugoslav federal state established by Tito. This was the first time Macedonia was recognized as a nation.