The Armenian–Azerbaijani War, which started after the Russian Revolution, was a series of brutal and hard-to-classify conflicts in 1918, then from 1920 to 1922 that occurred during the brief independence of Armenia and Azerbaijan and afterwards. Most of the conflicts did not have a principal pattern with a standard armed structure. The Ottoman Empire and British Empire were involved in different capacities: the Ottoman Empire left the region after the Armistice of Mudros but British influence continued until Dunsterforce was pulled back in the 1920s. The conflicts involved civilians in the disputed districts of Kazakh-Shamshadin, Zanghezur,