Between the years 1611 and 1620, a number of books supporting the Jacobean Oath of Allegiance were printed in London at the instigation of the English Government. The author's name on the title-pages of these books was given generally as “Roger Widdrington, an English Catholic”, sometimes simply as “Roger Widdrington”. Some of the books were in English, others were in Latin. Taken together, they represent what was probably the most learned and formidable defence of the Oath composed by any pen then active. At that time, the common opinion of those in a position to know, both in England and abroad, was that the name “Roger Widdrington” was a pseudonym which concealed the identity of the real author, the Benedictine priest, Thomas Preston. The modern accounts of his career given, for example, by Gillow (in his ‘Bibliographical Dictionary’) and by Thompson Cooper (in the ‘Dictionary of National Biography’) accept this traditional identification.