About the Mystery of the Letters the mid-6th century, in which Mar Saba had played an important role. The anonymous author of the treatise declares he was prompted to the study of the secret meanings of the letters by the words of the Apocalypse, "I am the Alpha and Omega", and that he subsequently received a vision about them on Mount Sinai. The author proposes a re-modelled Greek alphabet reduced to 22 letters on the model of the 22 letters of Hebrew (discounting Xi Ξ and Psi Ψ), and with the Hebrew letter names. He then interprets these letters as symbolic figures of 22 works of
Hebrew numerals + 300 + 60 + 7): To see how "today's" date in the Hebrew calendar is written, see, for example, Hebcal date converter. 5780 (2019–20) = תש״פ 5779 (2018–19) = תשע״ט 5772 (2011–12) = תשע״ב 5771 (2010–11) = תשע״א 5770 (2009–10) = תש״ע 5769 (2008–09) = תשס״ט 5761 (2000–01) = תשס״א 5760 (1999–00) = תש״ס The Abjad numerals are equivalent to the Hebrew numerals up to 400. The Greek numerals differ from the Hebrew ones from 90 upwards because in the Greek alphabet there is no equivalent for "Tsadi" (צ). Hebrew numerals The system of Hebrew numerals is a quasi-decimal