Humfrey, Duke of Gloucester (d. 1447) was the youngest brother of King Henry V (d.1422). He was a lover of books, and founded what subsequently became the Bodleian Library, Oxford. This manuscript was his own prayerbook, as shown by the inclusion of his heraldry, and by his ownership inscription on the final page. The text is similar to that of a psalter (having a calendar, psalms, litany, etc.), but is unusual because it contains only a selection of the 150 psalms. Many of the initials to psalms in the manuscript, including this 'D' and 'E', show an elderly bearded crowned figure. These presumably represent King David, supposed author of many of the psalms. As the younger brother of the king himself, such images would presumably have had a special resonance to Duke Humfrey.