Calenders in Books of Hours were sometimes illustrated with vignettes depicting the "labors of the months," seasonal actibvties, usually rural, performed by peasants throughout the course of the year. In this exceptional manuscript, however, the "labors" are depicted as full-page miniatures. Simon Bening, the last great Flemish illuminator, was famous in his lifetime, and had clients in Portugal, Italy, and Germany. The present manuscript, known as the Da Costa Hours, is named after its second owner, Don Alvaro de Costa, the armorer of King Manuel of Portugal.