The biography of Peter des Roches to 1231 can be written as merely one aspect of a wider history, charted in the standard accounts of the reigns of John and Henry III. But for the period after 1231 there exists no reliable narrative upon which to found an assessment of the bishop's career. What to date has been a study concentrated upon one man must be widened to comprehend the court as a whole; the factions and fortunes whose rise and fall frame the so-called ‘Poitevin’ regime of 1231 to 1234. The years in question are crowded with incident, including a war between king and barons, as significant in its way as the far more famous baronial wars of 1215–17 and 1264–5. To understand these events, to map their progress, motivation and consequences, we need first and foremost to establish a basic chronology. In addition, the regime of 1232–4 has been seen as bringing about two fundamental changes in English government: the importation to court of a large number of aliens, specifically Poitevins; and an attempt to overhaul royal finance leading to fundamental reforms in the administration of the Exchequer and the county farms. Both of these issues, financial ‘reform’ and the role played by aliens, will baulk large in what follows. Inevitably, des Roches must fade for a while from centre-stage, to take up a position in the wings.