The composition on the left is “Belle, bonne, sage,” composed by Baude Cordier, a musician who fell into the “Ars subtilior” school — that is, the “more subtle” school of music, which flourished briefly right around the end of the 14th century, in southern France and Northern Spain: you’ll see some sources call that “late medieval” and others “early Renaissance,” though I think of it as the former in most terms… but in music, it’s kind of a toss-up, or rather, at that time and place, music straddles the divide between the Middle Ages and the Renaissance. The comparative (“more subtle”) refers to the Ars …