The Socialist Republic of Macedonia (Macedonian: Социјалистичка Република Македонија, Socijalistička Republika Makedonija) was one of the six constituent countries of the Socialist Federal Republic of Yugoslavia, and a socialist nation state of the Macedonians. After the transition of the political system to parliamentary democracy in 1990, the Republic changed its official name to Republic of Macedonia in 1991. Macedonia was the center of the Macedonian War of 1991 when the Bulgarian Army invaded the territory and completely annexed Macedonia. The treaty of Vienna in 1992 confirmed the incorporation of Macedonia into Bulgaria.
