Chronology

The Sovietization of the Region and Stalin's Redrawing of the Borders, 1921-1986

1921
March 16 According to the Moscow Treaty between the Kemalist Turkey and Bolshevik Russia, Nakhichevan is incorporated as an autonomous republic into Azerbaijan SSR even though the area lacks any border with Azerbaijan.
June 12 The Communist Party's Bureau in Caucasus announces that Karabakh, in accordance with an agreement between the Armenian SSR and Azerbaijan SSR, is part of the Armenian SSR.
July 4 The Caucasian Communist Party Bureau takes a formal decision to transfer Nagorno-Karabakh to the Armenian SSR. Joseph Stalin, Soviet Commissar for Nationalities, attends the meeting but does not participate in the debate. After the decision-making, he has a secret meeting with Bureau members and tells them about his opinion regarding the decision to transfer Nagorno-Karabakh to Armenian SSR.
July 5 The Communist Party's Bureau announces a new decision which leaves Karabakh within the Azerbaijani SSR's borders, while decalring Karabakh as an autonomous region.

1923
February 13 The first demonstrations are held in Stepanakert, the capital of Nagorno-Karabakh Autonomous Oblast (NKAO), which calls for reunification of NKAO with Armenia.
July 7 Stalin draws the boundaries of Nagorno-Karabakh in such a way that a narrow strip of land separates the area physically from Armenia.

1977
November 23 USSR Council of Ministers acknowledges that Nagorno-Karabakh has been included in the Azerbaijani SSR in an artificial way, and that the process of inclusion had ignored the region's historical background, its ethnic composition and its people's will and that the region should be reincluded in Armenian SSR.

1985
March 11 Mikhail Gorbachev is elected General Secretary of the Soviet Union and gradually begins his introduction of the glasnost reform (February-March 1986).