Indulgences have long been studied as a contributory factor to the Protestant Reformation. The present essay focuses attention upon their origins in the eleventh century, and the changes that affected both the theology and the practice of indulgences in the period before 1215. The indulgences issued by English bishops tell us much of the role played in the English Church both by Parisian theology and by post-Gregorian theories of papal monarchy. They shed light upon the `birth' of purgatory, and upon twelfth-century penitential practice. The present essay also explores the relationship, previously ignored, between the indulgences advertised by pardoners, and the relics of the saints which pardoners were accused of mishandling.