Kublai was the second son of Tolui and Sorghaghtani Beki, and a grandson of Genghis Khan. Kublai's real power was limited to China and Mongolia. In 1271, Kublai established the Yuan Dynasty, which ruled over present-day Mongolia, China, Korea, and some adjacent areas, and assumed the role of Emperor of China. By 1279, the Yuan forces had overcome the last resistance of the Southern Song Dynasty, and Kublai became the first non-Chinese Emperor to conquer all of China. He was also the only Mongol khan after 1260 to win new conquests. The summer garden of Kublai Khan at Xanadu is the subject of Samuel Taylor Coleridge's 1797 poem Kubla Khan. This poem and Marco Polo's earlier book brought Kublai and his achievements to the attention of a wider audience, and today Kublai is a well-known historical figure.