Other notes and references :
The greek alphabetic numerals are attested since third century BC. (Ref. : Museum of Kairo, piece N° 65 445, published by Guéraud & Jouguet P., Kairo, 1938)
Still today all Greeks know this alphabetic numeration, next to the greek akrophonic numbers (similar to roman numbers) and the positional indo-arabic system.
During European Middle-Ages, the use of the greek alphabetic numerals – next to the official roman numbers – is attested, even inside West-Rom territories.
Virtually all the alphabets adapted the greek alphabetic numerals (hebrew, arabic, armenian, georgian, russian a. m. o. m. ) The use of original greek letters is
western standard during Middle-Ages. The doubtful, tardif adaption to the latin 23-letter alphabet (still without J, U & W) is however described by A. Kirchner,
in Oedipi Aegyptiaci, 1635, Volume II, pars prima, page 488 : with K = 10, T = 100 and Z = 500. – Since the 15th century indo-arabic system was adopted.
The performed, modern, latin alphabetic numeration was created in AD MCM.XCIII by Micheal Florencetime,
who put an invented, so-called « gamma-ny » – lower case « eŋ » – at the 15th place of a 27-latin-letter numeral alphabet.
The latin alphabetical numerals are used, notably by the years of lunar Eras, since they are also expressed by hebrew and arabic alphabetic numerals.