Georgia, one of the several countries that comprise the region known as the Caucasus, is a western Asian nation located on the shores of the Black Sea. Georgia is a country of extremely diverse terrain, represented in the nearly 100 different ethnic groups that comprise its population. The area of present-day Georgia contained the ancient kingdoms of Colchis and Kartli-Iberia. The Georgian identity has been closely tied to religion since the introduction of Christianity in the early 4th century. Despite centuries of foreign domination, Georgia has maintained a distinct culture, one influenced by both Asian and European traditions. Georgia was made a part of the Union of Soviet Socialist Republics in 1922. With the dissolution of the USSR, it became an independent, democratic republic. Some progress on market reforms and democratization has been made since then, but a government attempt to manipulate legislative elections in November 2003 sparked widespread protests and swept Mikheil Saakashvili into power in 2004.