A friend has passed on to me this link to an article in The Guardian about the discovery of one of King Henry VIII's books - a printed copy from 1495 of work by the fourteenth century English Franciscan William of Ockham - and the possible part it played in formulating the King's case for his divorce from Queen Catherine of Aragon. It can be viewed here.
Prof Carley, who identified the volume, is someone I have met and know. Reconstructing past Royal libraries is his current field of research, and a topic on which I have heard him speak. Previous to this he has made a major contribution to our understanding of the intellectual life of Glastonbury abbey in the middle ages.