Caesarius of Heisterbach is remembered for a paradoxical maxim concerning the rise and decline of monasteries according to which discipline causes prosperity in a monastery, and prosperity undermines discipline. He also gave the name of Titivillus as the demon who caused typographical errors in the work of scribes. He is further known as having attributed to Arnaud Amalric, a leader in the Albigensian Crusade, a famous declaration. Upon being asked how to distinguish Cathars from Catholics at the besieged town of Béziers, Arnaud supposedly replied "Caedite eos. Novit enim Dominus qui sunt eius", which translates as: "Slay them all, God will recognize his own." This statement is often cited as "Kill them all and let God sort them out."