Manuel Bryennios or Bryennius (Greek, Modern (1453-);: Μανουήλ Βρυέννιος; c. 1275 – c. 1340)[1] was a Byzantine scholar who flourished in Constantinople about 1300 teaching astronomy, mathematics and musical theory.[2] His only surviving work is the Harmonika (Greek: Ἁρμονικά), which is a three-volume codification of Byzantine musical scholarship based on the classical Greek works of Ptolemy, Nicomachus, and the Neopythagorean authors on the numerological theory of music.[2] One of Bryennios's students was Theodore Metochites, the grand logothete during the reign of Emperor Andronikos II Palaiologos (r. 1272–1328).[2] Metochites studied astronomy under Bryennios.[1] [2]