In a multiethnic, multireligious and multilinguistic society, ethnic tensions and regional interests commonly surfaced in both politics and daily life, especially between the two largest and most influential groups who monopolized all political power in the country, the Serbs and Croats. Other quarrels were those between Serbs and Macedonians, as the Yugoslav government had as its official position that the latter were ethnic Serbs from "Old Serbia" (). In the early 20th century the international community viewed the Macedonians predominantly as regional variety of Bulgarians on the basis on linguistics and cultural similarities, but during the Paris Peace Conference of 1919, the Allies sanctioned the Serbian control of Vardar Macedonia and its view, that Macedonian Slavs were in fact Southern Serbs. Bulgarian politicians later interpreted the decision as punishment for it being a Central Power during World War I and as sanctioned Serbian irredentism.