Giovanni dal Ponte- The Seven Liberal Arts (c. 1435) (source)
Each allegorical figure is accompanied by a historical luminary who also represents the discipline:
From left to right: 1) Grammar with Donatus (4th century) or Priscian (5th and 6th centuries), as well as two chidren; 2) Dialectics and Aristotle (Dialectics carries an olive branch as a symbol of peace among the Arts—as well as a scorpion, whose pincers represent the opposing positions of dialectical thought.); 3) Rhetoric and Cicero; 4) Astronomy (center), carrying the heavenly sphere, with Ptolomy sitting at his feet with one of the thirteen volumes of his history of Greek astronomy; 5) Geometry holding hands with Euclid; 6) Arithmetic and Pythagoras; and 7) Music with an organ followed by a figure that the Prado identifies as Tubalcain, its inventor—but maybe this is a mistake? The relevant passage is Genesis 4:20-22:
And Adah bare Jabal: he was the father of such as dwell in tents, and of such as have cattle. And his brother’s name was Jubal: he was the father of all such as handle the harp and organ. And Zillah, she also bare Tubalcain, an instructor of every artificer in brass and iron: and the sister of Tubalcain was Naamah.
So maybe it’s Jubal?