Russian interest in the Caucasus began early. In ad 943 Varangian, or Russified Norse, adventurers had sailed down the Caspian from the Volga River and captured the fortress of Bärdä. Subsequently, certain marriage alliances were concluded between the Russian and Georgian royal families, and in the 17th century Caucasian rulers were on several occasions forced to ask for Russian help against their enemies. Peter I the Great was the first to take advantage of the opportunities thus afforded to take possession of Caucasian territory. He occupied Derbent in 1722 and Baku in the following year. In 1770 Russian troops for the first time crossed the Caucasus range and took possession of Kʿutʿaisi. By 1785 all of the northern region of the Caucasus was designated as a Russian province; and, as already mentioned, Georgia was absorbed in the next century.
Two large groups of tribes in the middle Caucasus then acknowledged their subjection to the Russians, the Ossetes in 1802 and the Lezgians in 1803. Mingrelia fell in 1804 and the kingdom of Imereti in 1810. By the Treaty of Gulistan in 1813, Persia ceded to Russia a wide area of the khanates of the eastern Caucasus, from Länkäran northward to Derbent. Russia had little difficulty in acquiring by conquest from Persia in 1828 a stretch of the northern Armenian plateau, including the entire plain of Yerevan, and was able to take over more territory in the same area from Turkey in the following year.
The resistance of the mountain tribes, particularly of the Circassians of Abkhazia and the Lezgians of Dagestan, was more fierce and protracted. During 30 years, from 1815 to 1845, the Russians could do little more than hold these mountain peoples at bay. Some were sustained by patriotic feelings, others by religious fervour. The Circassians of the Western Caucasus were largely quelled between 1832 and 1839, but farther east in Dagestan resistance by the Muslim tribes was carried on longer. A holy war was declared by the sheikh Kasi Mullah (Ghāzī Muḥammad), and, after he was killed by the Russians, the struggle was continued by his successor Shāmil. Shāmil was finally captured in a remote fortress of Dagestan in 1859, though the main fighting had ceased four years earlier. Dagestan was completely pacified by 1864, after which almost the entire Circassian nation, numbering perhaps 400,000, preferring exile to subjection, emigrated into Ottoman territory, leaving the Western Caucasus empty and desolated.
Under tsarist rule a minority of the local peoples received some Western education and benefited from the relative prosperity and peace of the Russian Empire. Armenian, Georgian, and Azerbaijani intellectuals began to espouse nationalism and socialism, and by the turn of the 20th century revolutionary oppositions were gaining support in Tʿbilisi and Baku. Social democracy was the leading political movement among the Georgians, while more nationalist political principles, formulated by the Armenian Revolutionary Federation, dominated among the Armenians.
The Russian Empire benefited from the oil industry in Baku and conceived of its role in Caucasia as a civilizing mission. In the Russo-Turkish War of 1877–78, the Russian lines of communication in Armenia were ill-prepared, and the Turks were able to support an attempt by Circassian exiles to reoccupy their homeland. But this failed, and, by the Peace of Adrianople, Russia succeeded in adding to its Transcaucasian territories the districts of Kars, Batumi, and Ardahan.
In 1894–96, Armenians living in the Ottoman Empire, some of whom had formed nationalist political organizations, were massacred by Turkish troops and civilians and Kurdish tribesmen; in 1915 about 600,000 Turkish Armenians died or were killed while being forcibly deported to Syria and Mesopotamia.
After the collapse of tsarism in 1917 and the coming to power of the Bolsheviks, the Caucasians drifted toward independence. Rejecting the new communist government under Lenin, Transcaucasia declared itself independent in April 1918, but after a month three separate republics—Armenia, Azerbaijan, and Georgia—were proclaimed. After the communist victory in the Russian civil war, the Red Army was employed to establish Soviet power in the Transcaucasian republics.