Didymus the Musician (Greek: Δίδυμος) was a

music theorist Music theory is the study of the practices and possibilities of music. ''The Oxford Companion to Music'' describes three interrelated uses of the term "music theory". The first is the "rudiments", that are needed to understand music notation (ke ...

in Rome of the end of the 1st century BC or beginning of the 1st century AD, who combined elements of earlier theoretical approaches with an appreciation of the aspect of performance. Formerly assumed to be identical with the Alexandrian grammarian and

lexicographer Lexicography is the study of lexicons, and is divided into two separate academic disciplines. It is the art of compiling dictionaries. * Practical lexicography is the art or craft of compiling, writing and editing dictionaries. * Theoreti ...

Didymus Chalcenterus Didymus Chalcenterus (Latin; Greek: , ''Dídymos Chalkéderos'', "Didymus Bronze-Guts"; c. 63 BC – c. AD 10), was an Ancient Greek scholar and grammarian who flourished in the time of Cicero and Augustus. Life The epithet "Bronze-Guts" came f ...

, because

Ptolemy Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importanc ...

and Porphyry referred to him as Didymus ''ho mousikos'' (the musician), classical scholars now believe that this Didymus was a younger grammarian and musician working in Rome at the time of

Emperor Nero Nero Claudius Caesar Augustus Germanicus ( ; born Lucius Domitius Ahenobarbus; 15 December AD 37 – 9 June AD 68), was the fifth Roman emperor and final emperor of the Julio-Claudian dynasty, reigning from AD 54 unti ...

. He was a predecessor of Ptolemy at the

library of Alexandria The Great Library of Alexandria in Alexandria, Egypt, was one of the largest and most significant libraries of the ancient world. The Library was part of a larger research institution called the Mouseion, which was dedicated to the Muses, th ...

. According to Andrew Barker, his intention was to revive and produce contemporary performances of the music of Greek antiquity. The

syntonic comma In music theory, the syntonic comma, also known as the chromatic diesis, the Didymean comma, the Ptolemaic comma, or the diatonic comma is a small comma type interval between two musical notes, equal to the frequency ratio 81:80 (= 1.0125) ( ...

of 81/80 is sometimes called the ''comma of Didymus'' after him. Among his works was ''On the Difference between the Aristoxenians and the

Pythagoreans Pythagoreanism originated in the 6th century BC, based on and around the teachings and beliefs held by Pythagoras and his followers, the Pythagoreans. Pythagoras established the first Pythagorean community in the ancient Greek colony of Kroton, ...

'' (Περὶ τῆς διαφορᾶς τῶν Ἀριστοξενείων τε καὶ Πυθαγορείων).

Theory

We know of his theory only indirectly from the works of Porphyry and Ptolemy. There, one finds examples of his

tetrachord In music theory, a tetrachord ( el, τετράχορδoν; lat, tetrachordum) is a series of four notes separated by three intervals. In traditional music theory, a tetrachord always spanned the interval of a perfect fourth, a 4:3 frequency propo ...

s as measured string lengths from which the following proportions can be calculated: * diatonic tetrachord: (16:15)(10:9)(9:8) * chromatic tetrachord: (16:15)(25:24)(6:5) * enharmonic tetrachord: (32:31)(31:30)(5:4) Like

Archytas Archytas (; el, Ἀρχύτας; 435/410–360/350 BC) was an Ancient Greek philosopher, mathematician, music theorist, astronomer, statesman, and strategist. He was a scientist of the Pythagorean school and famous for being the reputed founder ...

, he used a

major third In classical music, a third is a musical interval encompassing three staff positions (see Interval number for more details), and the major third () is a third spanning four semitones. Forte, Allen (1979). ''Tonal Harmony in Concept and P ...

, but appears to have been the first to use it in the

diatonic Diatonic and chromatic are terms in music theory that are most often used to characterize Scale (music), scales, and are also applied to musical instruments, Interval (music), intervals, Chord (music), chords, Musical note, notes, musical sty ...

as the sum of the

major Major (commandant in certain jurisdictions) is a military rank of commissioned officer status, with corresponding ranks existing in many military forces throughout the world. When used unhyphenated and in conjunction with no other indicators ...

(9:8) and

minor Minor may refer to: * Minor (law), a person under the age of certain legal activities. ** A person who has not reached the age of majority * Academic minor, a secondary field of study in undergraduate education Music theory *Minor chord ** Barb ...

(10:9) whole tones as for the proportions (10:9)•(9:8)=5:4 obtains. The difference of these whole tones is the so-called syntonic comma, also referred to as Didymos' comma.

References

Sources

* * * Reprinted * *{{cite book , last=Richter , first=Lukas , chapter=Didymus idymos ho mousikos, chapter-url=https://archive.org/details/newgrovedictiona0005unse_j4w1/page/462/mode/2up , chapter-url-access=registration , editor-last=Sadie , editor-first=Stanley , editor-link=Stanley Sadie , editor-last2=Grove , editor-first2=George , editor2-link=George Grove , title=The New Grove Dictionary of Music and Musicians , title-link=The New Grove Dictionary of Music and Musicians , year=1995 , publication-place=London , publisher=Oxford University Press , orig-year=1980 , isbn=0-333-23111-2 , oclc=1245646411 , doi=10.1093/gmo/9781561592630.article.07752 , pages=462–463 1st-century Greek people Ancient Greek music theorists