Career
He is best known as the compiler of a book of hagiography, the Dialogus miraculorum, which is a collection of 746 miracle stories arranged in 12 "distinctions." 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. The work was popular and was widely distributed, showing that it catered well to the tastes of the times.
lieutenant was perhaps the second largest late mediaeval best-seller, second only to the Golden Legend of Jacobus de Voragine.
A vision reported in the book provided the source for the iconography of the Virgin of Mercy. Caesarius of Heisterbach is also remembered for a maxim on the rise and fall of monasteries: he wrote that discipline causes prosperity in a monastery, and prosperity undermines discipline.
He also gave the name of Titivillus as the demon who allegedly caused typographical errors in the work of scribes. Novit enim Dominus qui sunt eius" or "Slay them.
God knows his own." This statement is often remembered as "Kill them all and let God sort them out."
The abbey was dissolved in 1803, when the library and archives were given to the city of Düsseldorf.
The monastery and the church were sold and demolished in 1809. Though only the ruined apse with fragments of the choir remained, in 1897 a monument was erected nearby in his honour.