Caucasia, region in extreme southeastern Europe, situated between the Black Sea and Caspian Sea, and divided into two parts by the Caucasus Mountains. The portion to the north, known as the Caucasus (formerly Ciscaucasia), is characterized physically by gently sloping plains ending in low, marshy steppes. Lying within Russia, it contains the republics of Chechnya, Kabardino-Balkaria, Alania (North Ossetia), Dagestan, Karachay- Cherkessia, and Adygea. The southern and larger portion of Caucasia, Transcaucasia, is physically characterized by a rugged terrain, with chains of mountains (the Lesser Caucasus) running parallel to the central range of the Caucasus Mountains. This region consists of Georgia, Armenia, and Azerbaijan. Caucasia is noted for fertile lands, mineral deposits, and, in modern times, oil fields. Although Russian attempts to conquer the rich region, containing independent principalities, began early in the 18th century, the Russians assumed control in the 19th century after a series of wars with Persia and the Ottoman Empire, also disputing control over the region. The people of Georgia and Armenia, dominantly Christian, accepted Russian control as protection from Turkish persecution, but the Muslim population from the Caucasus bitterly fought it. Russian rule was marked by great severity and the repression of the native peoples. After the collapse of czarist Russia in World War I (1914-1918), the southern section of Caucasia became independent republics. In 1922 they became the Transcaucasian Soviet Federated Socialist Republic (SFSR), one of the four original union republics of the USSR. They separated again in 1936, however, becoming union republics in their own right. Caucasia was subjected to mass purges and executions under the Soviets; in 1943 almost all the Chechen, Ingush, Karachay, and Balkar peoples were deported to Siberia. The people of Caucasia are largely Muslim, with the exception of the Georgians and Armenians. Because some anthropologists have maintained that the Caucasus was the cradle of the white race, the word Caucasian has come to designate any white person (see Caucasian Race). Farming, livestock raising, and mining are the principal industries in Caucasia. Azerbaijan, Dagestan, Chechnya, and Adygea are noted particularly for the production of oil (at Baku, Groznyy, and Maykop, respectively). For further information on Caucasia see the various political units and divisions under separate headings. Total area of Caucasia, about 399,506 sq km (about 154,250 sq mi). Population (1989 estimate) 21,074,000.