The history of professional singers begins in the 16th century. Before this, professional musicians did not specialize in the voice or a particular instrument, and indeed such specialization became the norm only in the 19th century as a result of institutional training programs at conservatoires and academies of music. Where medieval and early modern treatises talk of the Latin musicus and cantor, they are distinguishing not between instrumentalists and singers, but between musical theorists or compo…