This article offers an effective and original interpretation of two crucial sources that have long baffled and misled modern historians, William of Malmesbury’s histories of Anglo-Saxon and Norman England, the Gesta regum and Gesta pontificum Anglorum. It focuses on their use of ambiguity, innuendo and legerdemain, showing that William was attempting to revive a set of rhetorical strategies for the writing of history which had developed in the Roman world and which had been defined most precisely by the Roman orator Quintilian. The argument is that his aim was typical of many other monastic historians of this time—to liberate his abbey from exploitation by its diocesan. But his method went well beyond the usual recourse to hagiography and forged charters to comprise a wholesale revival of classical historiography, because the abbey was taking on the king’s second-in-command, Bishop Roger of Salisbury (1102–39). Special methods were required in order to persuade others to oppose a man of such great power and to show them how it could be done.