Upon the disintegration of the Transcaucasian Federation with the proclamation of the independent Democratic Republic of Georgia on May 26, 1918, both Azerbaijan and Armenia proclaimed their independence on the same day, May 28, 1918. Both Armenia and Azerbaijan laid claim to the territory which they saw as historically and ethnically theirs; these territorial disputes led to the Armenian–Azerbaijani War between 1918 and 1920, a series of conflicts that ended only when both Armenia and Azerbaijan were annexed by the Soviet Union.