Reunification of Armenia
While Greece and Turkey battled in the east, the first Armenian Republic invaded the western portions of Turkey in 1919, reclaiming the historic lands of Western Armenia. The excuse the Armenian government gave for the invasion was to reunify the Armenian homeland and as reparations for the genocide of the thousands of Armenians that had been killed in 1915 and to prevent the Turkish government from killing more Armenians as word had reach the Armenian government of more villages being wiped out by Turkish military forces.
Unfortunately, the next year would see the invasion and annexation of the reunified Armenian homelands by the Soviet Union.
Like many of the countries which fell under Soviet rule, Armenian people found themselves controlled by a central authority that thought little of the Armenian culture. Churches were closed, the Armenian language was suppressed and the government in Moscow moved many Russian citizens onto Armenian land. Another way that the Soviet government tried to weaken the Armenian people was to forcibly move a large portion into Azerbaijan territory.
Post Soviet era
After the fall of the Soviet Union, the few remaining ethnic Russian populations either moved to areas along the Armenian coast of the Black Sea or completely assimilated into Armenia and now number less the 1%.
While some of the ethnic Russian citizens that moved into Armenia integrated into the Armenian culture, the group of Armenians on Azeri land has caused the minority Armenian population to either move out of Azerbaijan or congregate into a smaller area centered around the city of Xankendi. Because most of the people who now live in the area are of Armenian decent, groups started to form in the 1990's agitating for unification with the rest of Armenia or for independence.