This book examines the ways in which European queens engaged with De institutione foeminae Christianae (1524), the most popular instructional manual for women in sixteenth-century Europe. Vives (c. 1493-1540) dedicated the volume to Catherine of Aragon, queen of England as the wife of Henry VIII. Richard Hyrde did the same with his English translation. Juan Justiniano dedicated his Spanish translation to Germaine de Foix, dowager queen of Aragon as the wife of Ferdinand II. Catherine's support for De institutione and the association of its translations with a royal household, printer, or event became an important feature of its production and longevity. This book restores women to the history of De institutione and recovers a cultural understanding of its vernacular editions in England and Spain, especially with regard to queenship and public authority.