The Great Yasa of Genghis Khan was the law code promulgated by the founder of the Mongol Empire (also known as “Chinggis Khan” and spelled “Jenghiz Khan” in the document), who lived from 1162 to 1227. At its height, the Mongol Empire was the largest contiguous kingdom in history, stretching from the Sea of Japan to the Carpathian Mountains in central and eastern Europe. Thus, the Mongols ruled an empire of extremely diverse cultures, religions, and ethnicities. To study the Mongols, one must use sources written in Mongolian, Chinese, Russian, Persian, Arabic, Japanese, Korean, Latin, Old French, Armenian, Turkic, Georgian, and Syriac. Fortunately, many of the primary sources have been translated, making it easier for English-speaking scholars and students of history to understand the Mongol Empire. Nonetheless, the Great Yasa of Genghis Khan remains one of the least understood aspects of the Mongol Empire.