Dei gesta per Francos ("Deeds of God through the Franks") is a narrative of the First Crusade by Guibert of Nogent written between 1107 and 1108.
Traditionally it has not been well received by scholars, but recent translators and editors (such as Levine 1997 and Rubenstein 2002) have shown it to contain important original material.
He decided to undertake a history of the crusade, he says, after he read an anonymous eyewitness account called Gesta Francorum.
In the eyes of Guibert this work was rough and simple and "frequently left the reader stunned with its insipid vacuity" (Dei gesta, preface).
The fact that he stays so close to the original Gesta Francorum, and the difficulty of his Latin, make it seem superfluous.