FIRST OPENING OF EGYPT TO THE GREEKS 31 1 these circumstances a dense and regularly organized population should have been concentrated in fixed abodes along the valley occupied by this remarkable river, is no matter of vender ; the marked peculiarities of the locality seem to have brought about such a result, in the earliest periods to which human society can be traced. Along the five hundred and fifty miles of its undivided course from Syene to Memphis, where for the most part the moun tains leave only a comparatively narrow strip on each bank, as well as in the broad expanse between Memphis and the Mediter ranean, there prevailed a peculiar form of theocratic civilization, from a date which even in the time of Herodotus was immemo rially ancient. But when we seek for some measure of this antiquity (earlier than the time when Greeks were first admitted into Egypt in the reign of Psammetichus), we find only the com- putations of the priests, reaching back for many thousand years, first, of government by immediate and present gods, next, of human kings. Such computations have been transmitted to us by Herodotus, Manetho, and Diodorus, 1 agreeing in their essential conception of the fore-time, with gods in the first part of the series, and men in the second, but differing materially in events, names, and epochs : probably, if we possessed lists from other Egyptian temples, besides those which Manetho drew up at Heliopolis, or which Herodotus learned at Memphis, we should find discrepancies from both these two. To compare these lists, and to reconcile them as far as they admit of being reconciled, is interesting, as enabling us to understand the Egyptian mind, but conducts to no trustworthy chronological results, and forms no part of the task of an historian of Greece. To the Greeks, Egypt was a closed world before the reign of Psammetichus, though after that time it gradually became an important part of their field both of observation and action. The astonishment which the country created in the mind of the earliest Grecian visitors may be learned even from the narrative of Herodotus, who doubtless knew it by report long before he went there. Both the physical and moral features of Egypt stood in strong contrast with Grecian experience : " not only (?ay3 Herodotus) does the climate differ from all other climates, 1 See note in Appendix to this rhanUir.