First Nagorno-Karabakh War
Long before 1988 but especially in the late 1980s, the Armenian Soviet Socialist Republic had tried to put Nagorno-Karabakh under its sovereignty. Armenians sent letters and petitions to Moscow to make the unification come true, no matter when a political change happened there. According to Thomas de Waal's book "Armenia and Azerbaijan through Peace and War" (2013), on 3 March 1988, Gorbachev pointed out that the Politburo had failed to acknowledge such Armenian efforts as possible threats, saying "The Central Committee received five hundred letters in the last three years on the question of Nagorno-Karabakh. Who paid any attention to this?"