The Breviary of Queen Isabella of Castile is one of the most splendid of Flemish illuminated manuscripts, notable for the verve and originality of its miniatures. This is the first time it has been the subject of a substantial separate publication, providing comprehensive coverage of its contents and decoration. The manuscript was presented to Isabella by Francisco de Rojas, apparently to mark the occasion of the double marriage of her son and daughter to the children of Maximilian, King of the Romans, and his first wife, Mary of Burgundy. De Rojas had acted for Isabella and her husband, King Ferdinand of Aragon, throughout the marriage negotiations, which were concluded in 1495. Isabella had a strong interest in Flemish art and this sumptuous devotional book must have been much to her taste. Breviaries, normally produced for the use of the clergy, are much less common than books of hours. They contain a larger and more varied body of texts, affording their artists a wider range of subject matter and extensive decorative opportunities. In the case of the Isabella Breviary, no effort was spared to produce an illustrative scheme on a grand scale. Two outstanding workshops of the day are represented. The greater part of the manuscript is due to the Master of the Dresden Prayerbook, whose contribution includes a number of unusual Old Testament subjects. Many of the illustrations of saints are by the Master of James IV of Scotland. In addition there are four magnificent miniatures closely related to (and possibly in the hand of) Gerard David.