Reginald Pole (1500-1558), cardinal and archbishop of Canterbury, was at the centre of reform controversies in the mid 16th century - antagonist of Henry VIII, a leader of the reform group in the Roman Church, and nearly elected pope (Julius III was elected in his stead). His voluminous correspondence is a major source for historians of England, Catholic Europe and the early Reformation as a whole. In addition to the information on both secular and ecclesiastical political history, and the spiritual motives of reform, these letters provide real insight into humanist learning and cultural patronage in the Renaissance. This is the first of a five-volume project, making a vast body of material available for the first time, summarising each letter (and printing key texts), together with necessary identification and comment. The present volume covers the crucial turning point in Pole's career: his break with Henry VIII and his taking papal service. This encompassed the profound religious conversion which took Pole to the brink of one of the defining moments of the Italian Reformation, the writing of the Beneficio di Christo.