The “Documentary Hypothesis” originated when Jean Astruc (1684–1766) claimed he could identify the sources of the Bible by examining its use of divine names. His approach was later expanded by Julius Wellhausen (1844-1918), who identified four primary sources (J, E, D, and P) that he believed were combined to form the Pentateuch, also known as the Five Books of Moses. He based his theory in part on the consistent use of the names Elohim and Y-h-v-h in what he considered four writings by four different authors or groups. [Rabbi Dr. Israel Drazin]