 Various biographers have described him as a dictator, an autocrat, or accused him of practicing Caesarism.Montefiore argued that while Stalin initially ruled as part of a Communist Party oligarchy, in 1934 the Soviet government transformed from this oligarchy into a personal dictatorship, with Stalin only becoming "absolute dictator" between March and June 1937, when senior military and NKVD figures were eliminated.According to Kotkin, Stalin "built a personal dictatorship within the Bolshevik dictatorship".