We owe the refined adornments of the Torriani Book of Hours, it is believed, to the Lombard painter and illuminator, Giovanni Ambrogio de Predis (circa 1455-1509), the brother of the more celebrated Cristoforo de Predis. It is thought that he produced this splendid work in circa 1490-1495.

De Predis, Emperor Maximilian I

De Predis, Girl with cherries

 
Although specific confirmation is unavailable, a number of documents relate that De Predis produced enamel and illumination work. From 1472 to 1474, he worked with Cristoforo on two Books of Hours for Vitaliano and Francesco Borromeo. His name is mentioned in Rome as an “illuminator” (1491), and in 1503 and 1509 he trained two colleagues in the art of illumination.
Two miniatures for the “Grammatica” (grammar) by Elio Donato, for the eldest son of Ludovico Sforza, Massimiliano, can also be ascribed to him (housed in the Milanese library, Biblioteca Trivulziana).