I'm just starting with alternate history, so this might not be the most plausible POD, but if Peter of Aragon had followed the plan at the battle of Muret, could the Cathars have won the Albigensian crusade? Would occitania be more independent? What theological implications would come of Cathar preachers freely speaking throughout Europe? Any guidance on how to go about turning my first good idea into a good timeline would be great.