Meetings With Remarkable Manuscripts: An adventure in books

He did this simply to fit the manuscript into the new covers he had created.
The book was already a famous relic in Mullen’s time but that didn’t stop him. What’s more, there is no record of what he did with the offcuts — so, as Christopher de Hamel says in his superb book, if you have some old decorated strips of vellum lying around at home take good care of them, you could retire to a life of luxury on the proceeds.