Genghis Khan (August 18, 1227), born Temüjin, was the founder and first Great Khan (Emperor) of the Mongol Empire, which became the largest contiguous empire in history after his death. He came to power by uniting many of the nomadic tribes of Northeast Asia. After founding the Empire and being proclaimed "Genghis Khan" (an honorary title possibly derived from the Turkic "tengiz" — sea, meaning "the oceanic, universal ruler"), he launched the Mongol invasions that conquered most of Eurasia, reaching as far west as Poland in Europe and the Levant in the Middle East. Campaigns initiated in his lifetime include those against the Qara Khitai, Khwarezmia, and the Western Xia and Jin dynasties, and raids into Medieval Georgia, the Kievan Rus', and Volga Bulgaria.