BSIS was established by royal resolution in the autumn of 1945 to serve as the new infantry officer training school in the south of Norway. The new government formed by Einar Gerhardsen on 25 June 1945 had immediately initiated a comprehensive review of Norway's military capability after the end of hostilities with Germany on 8 May 1945. BSIS was established in order to complement Befalsskolen for Infanteriet i Trøndelag (BSIT), established 1804, and Befalsskolen for Infanteriet i Nord-Norge (BSIN), established in 1899, and would form the new backbone of army officer training in southern Norway.