The book of hours is a Christian devotional book used to pray the canonical hours. The use of a book of hours was especially popular in the Middle Ages and as a result, they are the most common type of surviving medieval illuminated manuscript. Like every manuscript, each manuscript book of hours is unique in one way or another, but most contain a similar collection of texts, prayers and psalms, often with appropriate decorations, for Christian devotion. Illumination or decoration is minimal in many examples, often restricted to decorated capital letters at the start of psalms and other prayers, but books made for wealthy patrons may be extremely lavish, with full-page miniatures. These illustrations would combine picturesque scenes of country life with sacred images. Books of hours were usually written in Latin (the Latin name for them is horae), although there are many entirely or partially written in vernacular European languages, especially Dutch. The closely related primer is occasionally considered synonymous with books of hours, but their contents and purposes could deviate significantly from simply recitation of the canonical hours. Tens of thousands of books of hours have survived to the present day, in libraries and private collections throughout the world. The typical book of hours is an abbreviated form of the breviary, which contains the Divine Office recited in monasteries. It was developed for lay people who wished to incorporate elements of monasticism into their devotional life. Reciting the hours typically centered upon the reading of a number of psalms and other prayers. A typical book of hours contains the Calendar of Church feasts, extracts from the Four Gospels, the Mass readings for major feasts, the Little Office of the Blessed Virgin Mary, the fifteen Psalms of Degrees, the seven Penitential Psalms, a Litany of Saints, an Office for the Dead and the Hours of the Cross. Most 15th-century books of hours have these basic contents. The Marian prayers Obsecro te ("I beseech thee") and O Intemerata ("O undefiled one") were frequently added, as were devotions for use at Mass, and meditations on the Passion of Christ, among other optional texts. Such books of hours continue to be used by many Christians today, such as the Catholic “Key of Heaven” prayer books, the Agpeya of Coptic Christianity or The Brotherhood Prayer Book of Lutheranism. History The book of hours has its ultimate origin in the Psalter, which monks and