An Allied Commission headed by U.S. Lt.Col. Sherman Miles inspected the situation in situ and recommended the Karawanken main ridge as a natural border to keep the Klagenfurt basin intact but, in agreement with item no. 10 of Woodrow Wilson's Fourteen Points, suggested a referendum in the disputed area. An armistice was agreed upon on 14 January and by 7 May 1919 the Yugoslav forces had left the state, but regular troops under Rudolf Maister returned occupying Klagenfurt on 6 June. Upon the intervention of the Allied Supreme Council in Paris they retreated from the city but remained in the disputed part of Carinthia until 13 September 1920.