In the Order of 31 July 1920 for the Reduction of the Army (to comply with the upper limits on the size of the military contained in the Treaty of Versailles), it was determined that in every Wehrkreis (military district) a division would be established by 1 October 1920. The 1st Division was formed in January 1921 out of the Reichswehr-Brigaden 1 and 20, both part of the former Übergangsheer (Transition Army).