The current conflict in Nagorno-Karabakh began in the second half of the 1980s, but its roots are deeper, reaching back at least to the first quarter of the 20th century. The aim of this article is to place these problematic aspects of mutual Armenian-Azerbaijani relations in their historical context and to link them with the current conflict. This article also identifies the factors that underlay the initial stages of the conflict and its subsequent escalation. The ethno-political mobilization of Armenians in Nagorno-Karabakh, but subsequently also of Armenians in the Armenian SSR and Azerbaijanis in the Azerbaijan SSR, was driven by specific conditions that emerged during the collapse of the Soviet state. The gradual ethno-political mobilization in both union republics, as well as in Nagorno-Karabakh itself, was a by-product of Soviet nationality policy, and was enabled by the policy of glasnost. This article identifies the following key factors that created suitable conditions for the escalation of the conflict: Armenians’ dissatisfaction with the autonomous status of Nagorno-Karabakh within Azerbaijan (fueled by the perception of numerous historic injustices), the legal and social chaos brought by the disintegration of the USSR, and the political and economic weakness of the newly emerging states.