- !9th century standard edition in latin of Dialogus miraculorum by Caesarius of Heisterbach (ca. 1180-ca. 1240), the prior of a Cistercian monastery, Heisterbach Abbey, which was located in the Siebengebirge, near the small town of Oberdollendorf, Germany. He 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." As an author, Caesarius of Heisterbach is best known as the compiler of a book of hagiography, this Dialogus miraculorum (ca. 1219-1223), a collection of 746 miracle stories arranged according to twelve distinctions.[4] The tales are told in the form of dialogues between a monk and a novice. The work was often referred to by preachers seeking material for sermons in the Late Middle Ages. It was extremely popular and was widely distributed, and its popularity was rivaled only, perhaps, by the Golden Legend of Jacobus de Voragine. A vision reported in the book provided the source for the iconography of the Virgin of Mercy. The contemplative writings of Caesarius can be seen as opposing the mendicant orders of his lifetime.