But it will be obvious that, if the theory is to be accepted in whole or in part, it must be shown to rest upon a firm historical basis, and that any inquiry into its credibility should be more fitly postponed until the history of the nation itself has been passed in review. After the evidence of actual contact with other races has been established in detail, it will be possible to form a more confident judgment upon questions which depend for their solution solely on a balancing of probabilities. The estimate of Babylon's foreign influence has therefore been postponed to the closing chapter of the volume. But before considering the historical sequence of her dynasties, and the periods to which they may be assigned, it will be well to inquire what recent excavation has to tell us of the actual remains of the city which became the permanent capital of Babylonia. [Footnote 1: Cf. Hogarth, "The Nearer East," pp. 212 ff., and Ramsay, "The Historical Geography of Asia Minor," pp. 27 ff. Herodotus (V, 52-54) describes the "Royal Road" of the Persian period as passing from Ephesus by the Cilician Gates to Susa, and it obtained its name from the fact that all government business of the Persian Court passed along it; the distances, given by Herodotus in parasangs and stages, may well be derived from some official Persian document (cf. How and Wells, "Commentary on Herodotus," II, p. 21). But it followed the track of a still earlier Royal Road, by which Khatti, the capital of the old Hittite Empire, maintained its communications westward and with the Euphrates valley.] [Footnote 2: At the present day this forms the great trunk-road across the highlands of Persia, by way of Kirmanshah; and, since the Moslem conquest, it has been the chief overland route from the farther East for all those making the pilgrimage to Mecca.] [Footnote 3: Cf. Hogarth, _op. cit.,_ p. 200 f.] [Footnote 4: See below, pp. 9 ff.] [Footnote 5: It is not improbable that the transference from one bank to the other was dictated by the relations of the ruling empire with Persia and the West.] [Footnote 6: See "Sumer and Akkad," p. 242.] [Footnote 7: Cf. Delitzsch, "Paradies," pp. 178 ff., and Meyer, "Geschichte des Altertums," 1., ii.; p. 473.] [Footnote 8: See below, Chap. IX., p. 280.] [Footnote 9: IV., 44.] [Footnote 10: Cp. Myres, "Geographical Journal," Mil. 1896, p. 623, and How and Wells, "Commentary on Herodotus," Vol. I., p. 320.] [Footnote 11: See Bevan, "House of Seleucus," I., pp. 242 ff., 253.] [Footnote 12: Cf. "Sum. and Akk.," p. 149.] [Footnote 13: As such the two cities were known as 'Al-'Irâkân, or Al-'Irâkayn, meaning "the two capitals of 'Irâk"; cf. G. Le Strange. "The Lands of the Eastern Caliphate," p. 25.]