In 1920–21 the only "solution" to this dispute could come either by military victory—as basically happened in Anatolia, Zangezur and Nakhchivan—or by the imposition from above of a new structure by an imperial power. After the British failed to impose a settlement, the imperial arbiters turned out to be the Bolsheviks, whose 11th Army conquered Karabakh in May 1920. On 5 July 1921 the Bolsheviks' Caucasian committee, the Kavbiuro, under the chairmanship of Joseph Stalin ruled that the mountainous part of Karabakh would be part of Azerbaijan.