Query: Who lead the rebellion against the 1211 settlement?
Context: John's strategy was to isolate the rebel barons in London, protect his own supply lines to his key source of mercenaries in Flanders, prevent the French from landing in the south-east, and then win the war through slow attrition. John put off dealing with the badly deteriorating situation in North Wales, where Llywelyn the Great was leading a rebellion against the 1211 settlement.