Calendar

The liturgical calendar was a vitally important component in the type of Christian devotion which spawned the book of hours. The calendar itself simply lists the feast day for a saint or event for every day of the year, along with a guide to determine the dates of those feasts for each year. Especially important feasts were written in red ink, whence we derive the term "red-letter day". The particular feasts listed in the calendar could vary from book to book. Many days have feasts for more than one saint, and there were also moveable feasts, which could be inserted whereever there was a gap in the calendar. Some books, like the Stuart de Rothesay Hours (British Library, Add MS 20927), do not have every day on their calendars filled in. The differences between books could arise from the personal preferences of their owners, and from regional variations in religious practices. In particular, the feasts which were marked in red for their liturgical importance reflected the regional rite for which the calendar was made, called the use. There were uses for the major cities of Rome, Paris, and Sarum (the Latin name for Salisbury, center of English Christianity), but also for provincial cities like Bourges, Amiens, Troyes, and Reims.

Though the calendar in Lewis & Clark College's book of hours is fairly plain, calendars in other books of hours could be quite ornate, with distinctive artwork reflecting the tastes and status of the original owner. These calendars often featured different illustrations for each month. The signs of the zodiac were a frequent subject, as were the seasonal activities of peasants and nobles. The latter were frequently presented in contrast to one another. For a famous example of an illustrated calendar, see the Très Riches Heures of Jean, Duc de Berry (Musée-Condé, MS 56). Other fine examples can be found in the Hours of Joanna I of Castile (British Library, Add MS 18852), the London Rothschild Hours (British Library, Add MS 35313), and the Huth Hours (British Library, Add MS 38126).