 It was probably written in the summer of 1081, at the urgency of Bishop Dietrich of Verdun, to whom it has also been ascribed.The form is that of an open letter to the pope; the tone is friendly, as though what he had to say was painful to the author.Wenrich disputes the efficiency of the emperor's excommunication (1080), opposes the laws of celibacy promulgated by the pope, condemns the inciting of the people against the emperor, defends investitures by texts of Scripture and the history of the Church, upbraids Gregory for being an accomplice in the setting up of a rival king, and reminds the pope that he himself has been accused of unlawful striving after the papal dignity, and even of the use of force to attain this end.