The Serbian Autonomous Oblast of Krajina (Serbo-Croatian: Srpska autonomna oblast Krajina / Српска аутономна област Крајина) or SAO Krajina (САО Крајина) was a self-proclaimed Serbian autonomous region (oblast) within modern-day Croatia (then a part of Yugoslavia). The territory consisted of majority-Serbian municipalities of the Republic of Croatia that declared autonomy in October 1990. It was formed as the SAO Kninska Krajina (САО Книнска Крајина), but, upon inclusion of additional Serb-populated areas, changed its name simply to SAO Krajina. In 1991 the SAO Krajina declared itself the Republic of Serbian Krajina, and subsequently included the other two Serbian SAOs in Croatia, the SAO Western Slavonia and the SAO Eastern Slavonia, Baranja and Western Syrmia.