 The book described itself as a chronicle of an early Israelite diaspora, integrating with the pre-existing indigenous peoples of the Americas, written by a people called the Nephites.According to The Book of Mormon, Lehi's family left Jerusalem at the urging of God c. 600 BC, and later sailed to the Americas c. 589 BC.The Nephites are described as descendants of Nephi, the fourth son of the prophet Lehi.