Archbishop Ebbo had been deposed in 835 at the synod of Thionville (Diedenhofen) for having broken his oath of fidelity to the emperor Louis, whom he had deserted to join the party of Lothair. After the death of Louis, Ebbo succeeded in regaining possession of his see for some years (840-844), but in 844 Pope Sergius II confirmed his deposition. In 845 Hincmar obtained through the king's support the archbishopric of Reims, and this choice was confirmed at the Synod of Beauvais (April 845). He was consecrated archbishop on 3 May 845; in 847 Pope Leo IV sent him the pallium.