Books of hours (Latin: horae) are Christian prayer books, which were 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 (they were largely known by the name horae until "book of hours" was relatively recently applied to them), 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 – a medieval horae was referred to as a primer in Middle English – but their contents and purposes could deviate significantly from the simple 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.
