Alypius, Greek music theorist who flourished in the mid 4th century. He wrote the invaluable Introduction to
Music (critical ed. by K. von Jan in Musici scriptores graeci, 1895), the chief source of specific information on ancient Greek notation. It contains a summary of Greek scales in all their transpositions, for both voices and instruments.
—Nicolas Slonimsky/Laura Kuhn/Dennis McIntire