The century-long struggle between Muslims and Armenians began in earnest in the Russo-Persian and Russo-Turkish wars of 1827-29. The basic features of that long battle were all seen in those first wars -- Russian invasion of Ottoman territory, Armenians siding with the invader, great Muslim mortality, forced migration of Muslims and a de facto population exchange of Muslims and Armenians.
In the 1827-29 wars in the east, a massive population exchange began, sparked by Russian expulsion of Muslims of the Erivan region. George Bournoutian has made use of Persian and Russian sources to estimate the population change in the Khanate of Erivan due to Russian conquest. He concludes that approximately 26,000 (30 percent) of the Muslims of the khanate either died or emigrated, based on a Russian population survey. Bournoutian further states that 45,000 Armenians had newly arrived in Erivan by 1832, "but it was not until the last quarter of the nineteenth century -- after the Russo-Turkish Wars of 1855-56 and 1877-78 brought more Armenians in from the Ottoman Empire -- that the Armenians established a solid majority in the region." Thus an Armenian majority came to pass in what today is the republic of Armenia, a majority prepared by the Russians. Erivan, approximately the area of the present Armenian Republic, was until 1827 an Iranian province with a Muslim (primarily Turkish) majority. The destruction or forced migration of the Muslim population allowed the Russians to repopulate the region with Armenians from Iran and the Ottoman Empire.