A serious conflict arose between archbishop Hincmar on the one side and Charles and the pope on the other in 876, when Pope John VIII, at the king's request, entrusted Ansegisus, archbishop of Sens, with the primacy of the Gauls and of Germany, and created him vicar apostolic. In Hincmar's eyes this was an encroachment on the jurisdiction of the archbishops, and it was against this primacy that he directed his treatise "De iure metropolitanorum". At the same time he wrote a life of St Remigius, in which he endeavoured by audacious falsifications to prove the supremacy of the church of Reims over the other churches. Charles the Bald, however, upheld the rights of Ansegisus at the synod of Ponthion.