High Quality Content by WIKIPEDIA articles! Russians (Bulgarian: , rusnatsi) form the fourth largest ethnic group in Bulgaria, numbering 15,595 according to the 2001 census, and mostly living in the large urban centres, such as Sofia, Plovdiv, Varna and Burgas. Although the largest wave of Russian settlers (White Guards) arrived following the events surrounding the October Revolution and the Russian Civil War, compact groups of Russians had been living in Bulgaria for centuries before that. Among the early Russian settlers were Old Believer Nekrasov Cossacks, some of which founded the village of Tataritsa in then-Ottoman-ruled Southern Dobruja (nowadays part of the village of Aydemir in Silistra Province) in 1674, building a church in 1750.