The political decision by the Bolshevist Government of the Russian Socialist Federative Republic (RSFSR) not to recognize the Azerbaijani Democratic Republic, the deployment of the Eleventh Red Army on the frontiers of the Azerbaijani Republic in Spring 1920, the aggression waged by Dashnak-ruled Armenia against Azerbaijan in Karabakh and Zangezur, terrorist strikes by Armenian groups and the Bolsheviks against the peaceful Azerbaijani population inside Azerbaijan and the social and economic crisis gripping the country - were all factors that combined to bring about a weakening of the Azerbaijani Democratic Republic and which led to the occupation of its capital by the Eleventh Army on April 27-28, 1920. As stated in a telegram from the general staff of the Caucasian front to the Eleventh Army command, dated May 1, 1920, the RSFSR troops had been instructed to take possession of the entire territory of Azerbaijan lying within the confines of the former Russian Empire, but without crossing the Persian border.
The next 70 years, during which it formed part of the Union of Soviet Socialist Republics (USSR), marked a new, important stage in the development of the Azerbaijani statehood, during which the Azerbaijan Soviet Socialist Republic forged ahead in its social, economic and cultural development. At the same time, however, the Soviet period also saw many negative trends emerge in Azerbaijan, as elsewhere throughout the USSR.
At the economic level, the country became a reservoir of fuel, raw materials and agricultural produce for the Soviet economy. At the cultural level, the imposition of the Cyrillic alphabet in place of the Latin alphabet severed the country's ties with the fountainhead of Azerbaijani literature and culture. The Soviet regime was at pains to suppress any efforts by the Azerbaijani intelligentsia to manifest their separate ethnic identity and to study the true history of their country.
During the Soviet period, the territories of Zangezur, Goycha, part of Nakhchivan and other districts were hived off from Azerbaijan and attached to neighbouring Armenia. As a result, the country's area, which in the period of the Azerbaijani Democratic Republic in 1920 was 114,000 square kilometers, was reduced in 1920-1921 to 86,600 square kilometers. In addition, on July 7, 1923 at the initiative of the Moscow leaders of the Bolshevists, the so-called Nagorno-Karabakh autonomous region, with a predominantly Armenian population, was artificially carved out of a part of the territory of historical Karabakh, the majority of population of which constituted Azerbaijanis. That decision marked the first step in the political campaign to amputate Nagorno-Karabakh from the rest of Azerbaijan.