William of Tyre
The "Chronicle of Ernoul" is found in a number of separate but similar manuscripts, stemming from an original source that does not survive but assumed to have been written by Ernoul himself. The basis of these is a 13th-century Old French translation of the Latin chronicle of William of Tyre, who wrote in the Kingdom of Jerusalem in the mid- to late-12th century. This French translation came to be known as the "History of Heraclius" or the "Estoire de Eracles", because William of Tyre began his chronicle with the reign of Byzantine emperor Heraclius.