I started Julius Wellhausen's Prolegomena to the History of Ancient Israel, his landmark nineteenth century work of biblical scholarship that divided the Pentateuch into four sources: J (the Yahwist), E (the Elohist), D (the Deuteronomist), and, finally, P (the priest). At the outset, what struck me about the book was that he appeared to be joining a discussion about sources that was already in progress, rather than starting the discussion himself. For example, he was trying to refute a scholar's notion that the priestly source was pre-exilic. Apparently, the debate was not just between Wellhausen and those who believed that Moses wrote the Pentateuch, for there were others who did not think that Moses wrote it, yet they had different ideas about its composition than Wellhausen.
In terms of the order in which Wellhausen believes that the sources were written, my impression so far is that it goes as follows: First, there was the Yahwist source, who believed that the Israelites could sacrifice anywhere that God revealed himself, or conduct their religious celebrations close to their homes. According to Wellhausen, we see in the Pentateuch stories in which the patriarchs and other biblical heroes set up altars and sacrificed in a variety of places, and Exodus 20:24-26 tells the Israelites to build an altar of earth or stone, and God will come to them in every place where he will record his name; this altar is unlike the altar of the priestly sources---the bronze one---so this must be a source that is different. For Wellhausen, the theme of worshiping at multiple authors is characteristic of the Yahwist, who supports freedom in worship.
Then, there are prophets, such as Hosea, Amos, and Isaiah, who (according to Wellhausen) do not oppose the existence of the high places---the multiple sanctuaries---but rather disapprove of the idolatry, the immorality, and the hypocrisy that are there. We don't see here the desire for a central sanctuary that is characteristic of the Deuteronomist and P, so, for Wellhausen, these prophets were prior to those authors.
Then there's the Deuteronomist. I'm not entirely sure when Wellhausen thinks that the Book of Deuteronomy was written, but he holds that Josiah attempted to implement its reforms in Judah during the seventh century B.C.E. The Deuteronomist promotes centralization, perhaps out of a desire to eliminate idolatry, and he vehemently contends against the existence of the high places, which shows that he's writing in a time when they were still a problem for him. For Wellhausen, that would fit Judah's pre-exilic period.
Then there's the priest, who is exilic and post-exilic. Unlike the Deuteronomist, he does not fight against high places in favor of a central sanctuary, but he simply assumes that the central sanctuary is where worship is to take place. According to Wellhausen, this fits the post-exilic period, even though the priests may have written in exile the laws that they planned to implement after Israel's restoration.
Wellhausen acknowledges that there were sacrifices in Israel's pre-exilic period, but he denies that they were tied to Moses, for Amos 5:25 and Jeremiah 7:22 acted like sacrifices were not even a part of Israel's sojourn in the wilderness after the Exodus (contra what we see in Leviticus and Numbers); rather, in Israel's pre-exilic period, sacrifices were merely seen as a way to satisfy the God of Israel, not as part of the law of Moses.
According to Wellhausen, the priests of the exilic and post-exilic periods developed nuances in the sacrificial system and tied the sacrifices to Moses. They even projected the Temple onto the wilderness by inventing the Tabernacle! Do you wonder why the Tabernacle is so absent from the historiographic books in the Hebrew Bible? Why is the ark so often apart from the Tabernacle, when (according to Wellhausen) "according to the law, the two things belong necessarily to one another" (page 41)? Why is the ark separated for so long from the Tabernacle---going from one place to the next, with no one even thinking of putting the ark inside of the Tabernacle? Why did David feel a need to pitch a tent for the ark of the Covenant in II Samuel 6, when he could have put it in the Tabernacle? And why does I Kings 3:2-3 apologize for Solomon offering sacrifices at the high place of Gibeon, if God's Tabernacle was there, as I Chronicles 1:39 states? Wellhausen's answer is that the historiographic books did not know about the Tabernacle, for they were written before the priests invented it. (The Chronicler wrote after P, so he knew about it.) And, when we see the tent of meeting in the historiographic books, Wellhausen chalks that up to interpolation.
On a side note, I read a piece in The Fundamentals (from the 1920's) that attempted to refute Wellhausen's arguments on the Tabernacle---on archaeological, textual, and text-critical grounds. It's by David Heagel, and it's entitled "The Tabernacle in the Wilderness: Did It Exist?" Some of his arguments were good. Some of them were bad. And I did not really know how to evaluate his archaeological arguments. But, leaving that aside, one thing that caught my eye was when Heagel said the following:
"So also, if we are to believe in the testimonies of ancient Egyptian monuments and the results of modern Egyptian explorations, there is many a resemblance which can be found to exist between matters connected with old Egyptian temples, their structure; furniture, priesthood and services, and other like matters appertaining to the Tabernacle. Indeed, some of these resemblances go so far in their minute details as to an arrangement of buildings according to the points of compass — a peculiarity which was found both in Egypt and in connection with the Tabernacle; different apartments in the structure, graded according to sanctity; the possession of a sacred ark or chest, peculiarly built and located; strange winged figures, which as existing in the Tabernacle were called "cherubim;" a gradation of the priests; priestly dress and ornaments; the breast-plate and mitre worn by the high-priest; different animals offered in sacrifice; the burning of incense, etc., that the impression left upon the mind of a person who knows about these things as existing in ancient Egypt and then reads in the Bible about similar matters connected with the Tabernacle is, that whoever wrote this Biblical account must himself have been in Egypt and have seen the old Egyptian worship and temples, in order to make his record conform in so many respects to what was found in that country."
Heagel is arguing that the Tabernacle existed because it resembled stuff in Egypt, which was where the Bible says that the Israelites were shortly before they made it. Heagel wants to boost the historicity of the Bible. But, in the process, Heagel says that there are similarities between Israel's religious system and that of Egypt. That sounds pretty liberal for The Fundamentals! Some conservatives get outraged at the notion that the Torah draws from Hammurabi, but David Heagel says that it copied from Egypt! And why does Heagel say that the Israelites got their religious architecture and system from Egypt? Why would they need to copy it, if God was the one revealing it to them? Heagel waxes eloquent with his fundamentalist rhetoric, and then he says something so liberal! For shame.