Tensions between John and the barons had been growing for several years, as demonstrated by the 1212 plot against the king. Many of the disaffected barons came from the north of England; that faction was often labelled by contemporaries and historians as "the Northerners". The northern barons rarely had any personal stake in the conflict in France, and many of them owed large sums of money to John; the revolt has been characterised as "a rebellion of the king's debtors". Many of John's military household joined the rebels, particularly amongst those that John had appointed to administrative roles across England; their local links and loyalties outweighed their personal loyalty to John. Tension also grew across North Wales, where opposition to the 1211 treaty between John and Llywelyn was turning into open conflict. For some the appointment of Peter des Roches as justiciar was an important factor, as he was considered an "abrasive foreigner" by many of the barons. The failure of John's French military campaign in 1214 was probably the final straw that precipitated the baronial uprising during John's final years as king; James Holt describes the path to civil war as "direct, short and unavoidable" following the defeat at Bouvines.
What was the final straw that precipitated the baronial uprising during John's final years as king?
The failure of John's French military campaign