It is from the shadow of a cloister that there emerges one of mankind's greatest very greatest scourges. Luther appears; Calvin follows him. The Peasants' Revolt; the Thirty Years' War; the civil war in France; the massacre of the Low Countries; the massacre of Ireland; the massacre of the Cévennes; St Bartholomew's Day; the murders of Henry II, Henry IV, Mary Stuart, and Charles I; and finally, in our day, from the same source, the French Revolution.