If the existing _ILIAD_ is a mass of "expansions," added at all sorts of dates, in any number of places, during very different stages of culture, to a single short old poem of the Mycenaean age, science needs an hypothesis which will account for the _ILIAD_ "as it stands." Everybody sees the need of the hypothesis, How was the medley of new songs by many generations of irresponsible hands codified into a plot which used to be reckoned fine? How were the manners, customs, and characters, _unus color_, preserved in a fairly coherent and uniform aspect? How was the whole Greek world, throughout which all manner of discrepant versions and incongruous lays must, by the theory, have been current, induced to accept the version which has been bequeathed to us? Why, and for what audience or what readers, did somebody, in a late age of brief lyrics and of philosophic poems, take the trouble to harmonise the body of discrepant wandering lays, and codify them in the _Iliad_? An hypothesis which will answer all these questions is the first thing needful, and hypotheses are produced. Believers like Mr. Leaf in the development of the _Iliad_ through the changing revolutionary centuries, between say 1200 and 600 B.C., consciously stand in need of a working hypothesis which will account, above all, for two facts: first, the relatively correct preservation of the harmony of the picture of life, of ideas political and religious, of the characters of the heroes, of the customary law (such as the bride-price in marriage), and of the details as to weapons, implements, dress, art, houses, and so forth, when these are not (according to the theory) deliberately altered by late poets. Next, the hypothesis must explain, in Mr. Leafs own words, how a single version of the _Iliad_ came to be accepted, "where many rival versions must, from the necessity of the case, have once existed side by side." [Footnote: _Iliad_, vol. i. p. xviii. 1900.] Three hypotheses have, in fact, been imagined: the first suggests the preservation of the original poems in very early written texts; not, of course, in "Homer's autograph." This view Mr. Leaf, we shall see, discards. The second presents the notion of one old sacred college for the maintenance of poetic uniformity. Mr. Leaf rejects this theory, while supposing that there were schools for professional reciters. Last, there is the old hypothesis of Wolf: "Pisistratus" (about 540 B.C.) "was the first who had the Homeric poems committed to writing, and brought into that order in which we now possess them."