Book of Hours
In the Middle Ages, the book of hours was the layperson's prayer and devotional book, which is supposed to sanctify the whole day through prayer at different hours (Latin horae, French livre d'heures). It follows the call from 1 Thess. 5:17: "Pray without ceasing!" and, in terms of structure and selection of its texts, is oriented towards the breviary that is obligatory for the clerics and the choral prayer of religious communities, but its overall design is not regulated. Since they are not only supposed to sanctify the individual days, there are often artistically illuminated annual calendars with feasts for Christ, the Virgin Mary, and the saints.