A book of hours is a type of devotional text which was widely popular during the Middle Ages. They are the most common type of surviving medieval illuminated manuscripts. Each book of hours contain a similar collection of texts, prayers, and psalms but decoration can vary between each and each example. Many have minimal illumination, often restricted to ornamented initials, but books of hours made for wealthier patrons can be extremely extravagant with full-page miniatures. These books were used for owners to recite prayers privately eight different times, or hours, of the day.