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
Xi (letter) Xi (letter) Xi (uppercase Ξ, lowercase ξ; ) is the 14th letter of the Greek alphabet. It is pronounced in Modern Greek, and generally or in English. In the system of Greek numerals, it has a value of 60. Xi was derived from the Phoenician letter samekh . Xi is not to be confused with the letter chi, which gave its form to the Latin letter X. Both in classical Ancient Greek and in Modern Greek, the letter Ξ represents the sound . In some archaic local variants of the Greek alphabet, this letter was missing. Instead, especially in the