This can be traced as far back as the seventh century B.C. on various grounds, and in all probability the traditional view which placed its introduction into Greece at about 660 B.C. is fairly correct. The earliest inscriptions on the vases are certainly not later, perhaps earlier than this (see below, p. 254). At Abou-Simbel in Egypt, Greek inscriptions have been found in which the name of Psammetichos occurs, and this king is generally supposed to be the second of that name (594–589).[2101] In Thera and other Aegean islands, and on the coast of Asia Minor, inscriptions are known which, for various reasons, have been placed even earlier than this, and the vase with Arkesilaos, the inscriptions on which are discussed below, is hardly later, as it can be shown to date between 580 and 550 B.C. Before proceeding to discuss the early inscriptions, it may be as well to note, for the benefit of those to whom Greek Epigraphy is an unfamiliar subject, the chief peculiarities of the earlier alphabets.[2102] They fall into two principal groups, the Eastern and Western, each of which has many subdivisions. Certain forms, such as [Χ] for Χ, are characteristic of one or the other division; but the distinction is not so clearly marked on the vases, on which many alphabets, such as the Ionic and Island varieties, are scarcely represented. The vase-inscriptions fall mainly under three heads: Corinthian and Athenian in the Eastern group, Chalcidian in the Western. During the fifth century (or even earlier) there is a rapid tendency to unification in the Greek alphabet, which is chiefly brought about by the growing supremacy of Athens. This acted in two ways: firstly, by the fact that Attic became the literary and therefore the paramount language in Greece; secondly, by the fact of her artistic pre-eminence, which crushed out the other local fabrics. Finally, by the time of the archonship of Eukleides in 403 B.C., the alphabet, if not the language, had become entirely unified, and the Ionic forms universally adopted for public and official purposes. For private use they had, of course, long been known at Athens; but the official enactment of that year only set the seal to a long recognised practice. Throughout the fifth century the old Attic and the Ionic forms are found side by side on R.F. vases.[2103]