According to the Graf-Wellhausen documentary hypothesis, the earliest strands are J, or the Yahwist, which is distinguished by its use of the name YHWH for the Israelite God, and E, the Elohist, which used the more generic term Elohim for God; D, the Deuteronomic source, dates to the late seventh century; P, the Priestly source, is post-Exilic (post-539 B.C.E). For more on the documentary hypothesis, see Joseph Blenkinsopp, “The Documentary Hypothesis in Trouble,” BR 01:04.