In the last there is the enormous displacement requisite to account for the utter absence of any population transitional to the Hellenic and Italian north of the Po on one side, and the Peneus on the other. But this--as, indeed, are all the others--is reducible to a question of displacement. Now it is the last four of the previous alternatives that are the most complicated. They are also those to which the current opinions most incline. The term Thraco-Pelasgic indicates this: since it shows that, instead of deriving the Greeks from the Italians, or the Italians from the Greeks, both are deduced from a third population. Upon this third population we must concentrate our attention; and define our ideas as to its conditions. If continuous, it must have been of considerable magnitude: and even if isolated, it can scarcely have been very small. Now the greater we make it the more mysterious is its present non-existence. It must have spoken a language intermediate in character to the Hellenic and Italian. Unless it did this it is of no avail. To be simply like the Greek is not enough; nor yet to be what is called Indo-European. It must be sufficiently transitional in character to act as a link. It must have been either ancient Albanian, which it cannot have been, ancient Thracian, which it is unlikely to have been, or, some third language winding itself into continuity between the most south-western Thracians and the most north-eastern Illyrians, _i.e._, populations akin to the Skipetar. So much for its conditions on the side of Greece. As it approached Italy they must been equally mysterious. Unless we suppose the Liburnians and Venetians to have spoken such a tongue it must have lapped round the area of the northern populations of the Adriatic, so as to be thrown considerably westwards. But, to all appearances, Circumpadane Etruria began where the Veneti and Liburni left off. The special classical scholar best knows how far the Pelasgi--how far, indeed, any ancient populations--fulfil these conditions. Of course, by assuming an unlimited amount of displacement and migration they can be made to do so. But such assumed displacements may be illegitimately large. Whether they are so or not depends upon the extent to which they are necessary. Such is a sketch of the difficulties involved in the hypothesis that Greece and Italy were appropriated by similar populations by means of migrations by _land_.