It was early observed, however, that there are numerous expressions in the Pentateuch which assume the settlement of Israel in Canaan and look back to the age of Moses as to a somewhat remote past: Gen. xxxvi. 31, for example, implies the existence of the Israelite monarchy. In the seventeenth century such anachronisms were bandied about a good deal, but, inasmuch as they were all brief clauses which might well be notes or glosses by scribes, they proved nothing about the age of the main text. The controversy sharpened the eyes of the critics, and many more conclusive facts were brought to light, which proved that the Pentateuch was not the product of one author nor of one age, and that, whatever part Moses may be conceived to have had in it, much must be ascribed to later writers. No methodical attempt had been made, however, to distinguish its different strata, or to discover the sources from which it was compiled. This was first undertaken by an eminent French physician, Jean Astruc, who in 1753 published the results of his investigations under the modest title "Conjectures concerning the Original Memoirs which it appears that Moses used in compiling the Book of Genesis." Astruc's analysis was suggested by peculiar phenomena in the use of the divine names in Genesis, and he was led to the hypothesis that Moses had for the primeval and patriarchal history two principal sources, one of which employed consistently the proper name Jehovah, the other the appellative Elohim (God). The two narratives were in large part parallel, and when they were united in one continuous narrative, repetitions, contradictions, and chronological difficulties were created which disappear when the sources are separated and recombined in their original sequence. This is not the place for a history of criticism: it must suffice to say that, as the result of the labours of many scholars in the last century and a half upon the problem of the sources and composition of the Pentateuch, historians are now generally agreed that four main sources are to be recognized, of which three run, in varying proportion, from Genesis to Numbers and reappear in Joshua, while the fourth is found in Deuteronomy and Joshua only. CHAPTER IV CHARACTER OF THE SOURCES: GENESIS Of the four main sources of the Pentateuch and Joshua, two are easily recognizable, and may be distinguished with certainty in almost any combination. The Book of Deuteronomy, though itself a composite work, constitutes a whole, with a characteristic religious point of view and marked peculiarities of language and style. The strand akin to it in Joshua is not always so easy to discriminate from additions and editorial retouchings in one of the other sources; but since these are of approximately the same age, the difficulty is, from the historian's point of view, not of very serious moment.