History of the Greek alphabet derive from omicron with a line drawn under it. Long and were written with the digraphs "ει" and "ου", respectively, whereas long and short , , were never distinguished in writing. In 403/2 BC, following the devastating defeat in the Peloponnesian War and the restoration of democracy, the Athenians voted to abandon the old Attic alphabet ("Pre-Euclidean alphabet") and to introduce a standardized variant of the eastern Ionic alphabet, after a proposal by archon Eucleides. This Euclidean alphabet included eta and omega, which concluded the process of adapting the Phoenician script so that all vowels could be written systematically, thus
History of the Greek alphabet foreshadowed the development of vowel letters with a limited use of "matres lectionis", that is, consonants that pulled double duty as vowels, which for historical reasons occurred mostly at the ends of words. For example, the two letters "wāw" and "yōdh" stood for both the approximant consonants and , and the long vowels and in Phoenician. By this point in time, Greek had lost its sound, so Phoenician "yōdh" was used only for its vocalic value, becoming the Greek vowel letter iota . However, several Greek dialects still had a sound, and here "wāw" was used for both of its