Historically, until the Russian conquest , the Western Circassians lived in free tribal societies whereas the Eastern Circassians (mainly the modern day Kabardians) fashioned a highly stratified aristocratic society. Having survived the Mongolian, Khazar and Alan invasions throughout two millenniums they encountered with the Tsarist Russian Armies in the first half of the 19th Century. As all the other North Caucasian peoples they fiercely fought the Russian Army but were defeated and decimated by it in 1864. As a result of the Russian conquest, the overwhelming majority of the Circassians, around 1.200.0000, were forced to flee to the Ottoman lands of whom around 800.000 (4) survived the tragic exodus. Their descendants today comprise a sizeable Circassian Diaspora in Turkey and the Middle East.

http://www.kafkas.org.tr/english/tarih/circassian_karachai_essay_.html

The Circassians who had remained in the North Caucasus participated, with the other North Caucasian peoples, in the short-lived independent state of Mountaineers Republic of the North Caucasus formed in 1918,which became part of the new Soviet Union and was renamed the Soviet Mountain Republic in 1921. Within a few years the Mountain Republic disintegrated and the Circassians were divided into three categories as the Adyge (self designation in Circassian language), the Cherkess (name by which the Circassians by then had been called by the Turks and the Russians) and the Kabardians (name of the one of the biggest tribes of the Circassians).