Genghis Khan (1162-1227) was the founder, Khan (ruler) and Khagan (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 Mongol Empire and being proclaimed "Genghis Khan," he started the Mongol invasions that would devastate most of Eurasia. These included raids of the Kara-Khitan Khanate, Caucasus, Khwarezmid Empire, Western Xia and Jin dynasties. These campaigns were often accompanied by wholesale massacres of the civilian populations - especially in Khwarezmia. By the end of his life, the Mongol Empire occupied a substantial portion of Central Asia and China. Before Genghis Khan died, he assigned Ogedei Khan as his successor and split his empire into khanates among his sons and grandsons. Beyond his great military accomplishments, Genghis Khan also advanced the Mongol Empire in other ways. He decreed the adoption of the Uyghur script as the Mongol Empire's writing system. He also promoted religious tolerance in the Mongol Empire, and created a unified empire from the nomadic tribes of northeast Asia. Present-day Mongolians regard him highly as the founding father of Mongolia."