Book of HoursThis was an ornate medieval or Renaissance prayer book, hand written on vellum and invariably illuminated with pictures.
It contained the Little Office for the Blessed Virgin and usually a liturgical calendar, penitential psalms, litanies, the Office of the Dead and sometimes other material.
Such books were most popular in the 15th century. Many of the most splendid examples are French, such as the 'Très Riches Heures' of the Duc de Berry.
The National Gallery, Trafalgar Square, London WC2N 5DN