As many families did, several owners of the Keble-Petre Hours recorded aspects of their family history in the pages of the book, documenting important events the family experienced. During the later Middle Ages, societal shifts saw the rise of the merchant classes, and these newly well-to-do families felt it was important to document their history and connections with other families. A Book of Hours, which could be added to and passed on for generations, was a convenient site for such documentation, serving as a working family tree.