Some medieval books contain one or more specific texts that belong together since their inception. There are also medieval books where separate manuscripts ended up together, but they have no connection with each other. A later owner of the texts combined them into one book. These books are called ‘convolutes’. An example of such a convolute is Ms. 688 from the Utrecht University Library. It contains several medical and astrological texts that are written down over a span of more than 100 years and ended up together in one book.