This is a book about politics, power and national identity, as reflected in the life of one particular man. For a period of more than thirty years Peter des Roches exercised an influence over the politics of the Plantagenet court greater, arguably, than that of anyone else save King John. His influence will bear comparison to that of Robert Walpole over the Hanoverian court, or of cardinal Richelieu over the Bourbon kings of France. Amongst des Roches' contemporaries, only one other courtier, Hubert de Burgh, commanded the same magnitude of authority, and in Hubert's case, this was an authority restricted to a far narrower span of years. Yet, whereas de Burgh has formed the subject of at least one full-scale study, and whereas many books have been written on the lives of King John and his son, King Henry III, there has to date been no attempt to present a detailed biography of Peter des Roches.

In part, this omission reflects the nature of the sources. Des Roches, so far as we know, was not commemorated by any contemporary biographer in the way that Thomas Becket inspired a host of writers, or William Marshal the epic Histoire de Guillaume le Maréchal. He was neither a saint, nor a scholar. Beyond a highly formal series of diocesan statutes, and a collection of one hundred or so charters issued in his capacity as bishop of Winchester, he left behind no corpus of writings – nothing to compare to the letter collections of politician bishops such as Arnulf of Lisieux and Gilbert Foliot, or to the literary output of the scholars Stephen Langton and Robert Grosseteste.