A breviary is a prayerbook giving the prayers, hymns, and readings for the divine office, the cycle of devotions which monks recited daily. They can vary in size, this one being on the small side and so considered a 'portable breviary.' Its origins are uncertain, although heraldry of the Despenser, Warren, and other families were added to it soon after its manufacture. In 1486 Thomas Harwode, chaplain, gave it to the parish church of Penwortham, Lancashire. The Penwortham Breviary preserves one of the oldest, most complete examples of the divine office according to Sarum Use, or as recited in much of medieval post-Norman England. The psalter (Book of Psalms) is included in the breviary because the monks sang from it daily. The first letter of Psalm 38 (39), 'I will keep my tongue from sin', has a picture of David pointing to his mouth as he addresses Christ. In medieval breviaries and psalters, psalms were often illustrated as Christian hymns, with Jesus often depicted even though they were composed before he was born.