The Hebrew Bible and the historical issues surrounding it is one of my major areas of study/geeking. Frankly, I am surprised that I have gone this long without talking about it in here.
The Documentary Hypothesis was founded in the nineteenth century by Julius Wellhausen. It is also known as Biblical Source Theory. This theory states that there are four main sources making up the books of Genesis, Exodus, Leviticus, Numbers, Deuteronomy, Joshua, Judges, ISamuel, IISamuel, IKings, and IIKings.
The four sources are as follows:
J = Yahwistic
E = Elohist
P = Priestly
D = Deuteronomistic
The J source originated in the southern kingdom of Judah. It is called J, or Yahwistic, because the J texts use “Yahweh,” or the Hebrew letters “yod hay vav hay” to refer to god. The E source originated in the northern kingdom of Israel and is called E, or Elohist because those texts referred to god as either El–the chief god of the Phoenician pantheon and the father of Ba’al–or Elohim, meaning “gods.” The implications of this will be discussed in a separate post.
When the kingdom of Israel was sacked by Assyria in 722 BCE, many of its citizens fled south into Judah, bringing their holy texts, the E source, with them. Because Israel and Judah shared the same general religious beliefs and oral traditions, J and E were easily combined into one text, which I will refer to from this point on as JE.
JE can be found in Genesis, Exodus, Leviticus, and Numbers. The Priestly source was written much later than JE as a theological response to said text; P objected theologically to several issues within the JE text, but mainly to the manner in which it depicted human communication and interaction with god. It was likely written in the late eighth century, and it is very possible that P intended his text to function as an alternate Torah. If this is the case, it is rather ironic; P was combined almost seamlessly with JE in the sixth century by an editor known as the Redactor. Like JE, P can be found throughout the books of Genesis through Numbers.
D is responsible for the writing of Deuteronomy through IIKings. The D source was written during the seventh century reign of King Josiah when D was charged with writing a history of the Israelite people up to that point in time. It is very likely that the Deuteronomist was drawing from much earlier historical material in his writing, but those documents are long gone. King Josiah was carrying out many religious and political reforms during his reign, and the politics embedded within the D books of the Bible reflect this.
While I feel safe saying that the books of Genesis through Joshua have no basis in historical fact, Judges through IIKings contain varying amounts of legitimate history. A good deal of the material in Judges-IIKings has been corroborated by archaeological finds, and by texts left behind by contemporary polities. There is a lot of debate about this within the scholarly community, but I attribute this more to the fact that historians, archaeologists, literary critics, and linguists have trouble working cooperatively and embracing interdisciplinary scholarship than to any other reason.
IIKings ends with the 586 BCE Babylonian conquest of Judah. A second source known as D2 wrote the last chapters of IIKings, which give the history of Judah through the death of Josiah to the fall of Judah.