The establishment of the Mongolian Empire in the early 13th century was the work of Genghis Khan (ca. 1162–1227), one of the greatest chiefs of all time. During his lifetime, he divided the state between his four sons. The westernmost part of the empire, known as the Golden Horde (or traditionally the Ulus of Jochi), included vast territories of Eastern Europe and northern Central Asia. The Golden Horde (1242–1502) flourished the most in the first half of the 14th century, but its downfall began just around a dozen years later. In the 15th century, the Crimean Peninsula, which had been its integral part for two centuries, passed into the hands of an autonomous dynasty of the Girays, who established the independent Crimean Khanate (1441–1783).