Studied in the current literature solely for his miniature work at the court of Henry VIII, Lucas Horenbout (d.1544) was equally sought after as an illuminator of prayerbooks. His career in this genre marks an important inflection point in the history of English art. The late 15th and early 16th centuries saw the final fluorescence of the illuminated prayerbook. This occurred side-by-side with a publishing revolution anchored in new technology that changed the parameters of book production and distribution. The Reformation, together with the advent of the printing press, combined to transform the market for illuminating skills Lucas had learned in his father’s workshop in Ghent. His artistic output between 1530 and 1544 bridges the transition from traditional handwritten, hand-illuminated manuscripts to the modern, mass-produced printed book. This paper discusses that transition through Horenbout’s proposed work in five illuminated prayerbooks created for four different patrons: Henry VIII, Anne Boleyn, Kateryn Parr and Anne Stanhope, Countess of Hertford and later Duchess of Somerset, as well as his collaborative additions to the 1539 Great Bible under the patronage of Thomas Cromwell. Horenbout’s career demonstrates how an elite artist adapted his art both to a changing marketplace and to the shifting power politics of the Tudor court.