In the past the House of Lords has been the Cinderella of parliamentary history. This volume makes amends for the omission. It is the first systematic institutional study of the sixteenth-century Upper House. Not only does it chart its composition and quality, its record of attendance, activity and conflicting centrifugal and centripetal forces, it also examines the role of the legal assistants, who contributed so much to its efficiency as a legislative machine, analyses its procedures and assesses its legislative record in the mid-Tudor parliaments. In the process it also sets the Edwardian and Marian Commons in their right perspective. The Lords emerges as a vital party in the legislative process. Until 1553–5 its performance was, more often than not, superior to that of the Commons. But then it reneged on its political responsibilities and resisted the Crown in a rare act of sabotage - the most effective of the sixteenth century. It did not recover.