This very special live episode of EXplaining History features a discussion exploring the exciting new work of Dr Gregory Lippiatt on the political and social consequences of the Albigensian Crusade, exploring how state and religious powers negotiated the heretic worlds that developed in the south of France in the 12th century (listeners excited to be entertained with proper hellfire and the invocation of demons will have to be contented with the popularisation of veganism-- but how could veganism invoke such dangers for church authority? Dr Lippiatt explains all). Listeners interested in Pennsylvania will be fascinated to discover that John and Gregory both grew up in the keystone state, and they compare childhood experiences of exploring historical PA sites from Gettysburg to the underground Benjamin Franklin Museum.