- Andrew Barker
Author of significant writings on harmonics. (See music § 5.) His novel techniques on the monochord and his original, rather straightforward tetrachordal divisions are closely criticized by Ptolemy (Harm. 2. 13–14). *Porphyry quotes extensive passages (On Ptolemy's Harmonics 26. 6–29, 27. 17–28. 26) on distinctions between schools of harmonic theory, developed elaborately from the female musicologist *Ptolemaϊs, and cites Didymus as authority for a report known to Ptolemy (Harm. 1. 6), originating with *Archytas, about early Pythagorean procedures. Porphyry also alleges that Ptolemy took much of his material from Didymus without acknowledgement; this is no doubt an exaggeration, but there may be some truth in it, particularly as regards his information about Archytas and the Pythagorean theorists. He is perhaps the Suda's Didymus son of Heraclides, a grammarian and eminent musician of Neronian times.