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
Albanian alphabet and Jani Vreto created an alphabet. This was based on the principle of "one sound one letter" (although the revision of 1908 replaced the letter "ρ" by the "rr" digraph to avoid confusion with "p"). This was called the "Istanbul alphabet" (also "Frashëri alphabet"). In 1905 this alphabet was in widespread use in all Albanian territory, North and South, including Catholic, Muslim and Orthodox areas. One year earlier, in 1904 had been published the Albanian dictionary () of Kostandin Kristoforidhi, after the author's death. The dictionary had been drafted 25 years before its publication and was written in the Greek