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
DEC Hebrew 250 in all three character sets. In the following table, code points that differ from DEC MCS are shown boxed. DEC Hebrew The DEC Hebrew character set is an 8-bit character set developed by Digital Equipment Corporation (DEC) to support the Hebrew alphabet. It was derived from DEC's Multinational Character Set (MCS) by removing the existing definitions from code points 192 to 223 and 224 to 250 and replacing code points 251 to 256 by the Hebrew letters. Since MCS is a predecessor of ISO/IEC 8859-1, DEC Hebrew is similar to ISO/IEC 8859-8 and the Windows code page 1255, that