Excerpts from Books and Wikipedia
"The expansion continued after Genghis Khan's death in 1227, creating the largest contiguous land empire in world history." [Furtado: 1001 Days] "Genghis also developed a legal code for his people, called the Jasagh or Yasa. He learned about cities from the Muslims and farms from the Chinese. He respected tradesmen and artisans and often spared them in his conquests. Religiously tolerant, he welcomed Buddhists, Christians, Taoists, and others to his court. According to a Persian historian, he 'used to hold in esteem beloved and respected sages and hermits of every tribe, considering this a procedure to please God.'" [National Geographic Almanac, p. 156]