Second Balkan War
While Serbia, Greece and Bulgaria came out on top in their unified campaign against their common aggressor, the agenda by the Bulgarians to take a larger share of land caused Greece and Serbia to join in a defensive front and to secure their existing borders.
Bulgaria, wishing to impose territorial requirements, unleashed attacks against Greek and Serbian forces in June of 1913. With Romania, Montenegro, but also the Ottoman Empire to complement the common defense, Bulgaria had no choice but to give up their fight. The final boundaries between the feuding Balkan states were cemented with the signing of the Bucharest Treaty, on July 28th, 1913. Under the agreement, Greece retained Macedonia, Epirus, the northern Aegean islands and Crete, which was formally annexed on December 1st of that same year.