Jevons goes on to give the grounds for the conclusion (based mainly on the formation of certain of the letters, and in part, of course, on the references to King Psammitichus) that the inscription was written, or rather was cut, upon the statue between 620 B.C. and 600 B.C., according as we take the king mentioned to have been the first or second of his name.[23] We have, then, a date fixing a time at which the art of writing certainly existed among the Greeks, while it is further evident that if in the year 600 the art of writing was so well established that it was understood by a number of mercenaries, it must have been quite generally diffused through certain classes of society, and the date for its introduction into Greece must have been considerably earlier than 600. Jevons knows, however, of no example of Greek writing which can be ascribed to an earlier date than that above quoted. The conclusion, based upon this inscription, that in the year 600 B.C. writing had for some time been known in Greece, enables us, however, says Jevons, to accept as probably authentic a reference to writing ascribed to an author who lived nearly a century earlier. Archilochus, a poet who is believed to have flourished about 700 B.C., uses in one of his fables the expression “a grievous _skytale_.” “A _skytale_ was a staff on which a strip of leather for writing purposes was rolled slant-wise. A message was then written on the leather, and the latter being unrolled, was given to the messenger. If the messenger were intercepted, the message could not be deciphered, for only when the leather was rolled on a staff of precisely the same size (_i. e._, thickness) as the proper one, would the letters come right. Such a staff, the duplicate of that used by the sender, was of course possessed by the recipient.” This primitive method of cipher was for a long time in use with the Spartans for conveying State messages. In the figure of speech used by Archilochus, his fable was to outward appearance innocent of any recondite meaning, but would prove a grievous “skytale” for the person attacked. It seems reasonable, continues Jevons, to accept this passage as indicating a knowledge of writing in Greece as early as 700 B.C. This date allows a century for the diffusion of the art and for the spread of the Ionic alphabet which are implied by the Abu Simbel inscription. And the passage does not prove too much. It does not imply even that Archilochus himself could write. The invention or introduction was sufficiently novel and admirable to furnish a poet with a metaphor; and the _skytale_ was probably then, as in later times, a government institution. This mention of it accords with the probable supposition that writing was used for government purposes for some time before it became common among the people.