Inspired by the Visconti Hours, which was commissioned by Gian Galeazzo Visconti, who ruled Milan as duke from 1351–1402. His love of books originated with his wife Isabella, the sister of Jean Duc de Berry. Visconti enlisted Giovannino de Grassi, one of the most talented painters of his time, to artistically decorate his Book of Hours. When the latter died, Belbello da Pavia continued the work, which was completed under Gian Galeazzo's son c. 1430.