Jewish Italian dancer and dancing master at some of the most influential courts in Renaissance Italy (c. 1420 - c. 1484).
Author of the treatise "De pratica seu arte tripudii" (On the Practice or Art of Dancing), sometimes cited as "Trattato dell' arte del ballare" (Treatise on the Art of Dancing). It contains choreographies and music for thirty-six dances by Guglielmo and his contemporaries.
Between October 1463 and May 1465, Guglielmo probably converted from Judaism to Roman Catholicism and took the name Giovanni Ambrosio.