[1] In 857, the Annales Bertiniani reported that a dog sat on the archiepiscopal throne of Trier, which was interpreted as an omen portending the fall of Theotgaud.
They were summoned before the Lateran Synod of October 863, where Nicholas, suspecting the legates had been bribed, anathematised the council and deposed Theotgaud and Gunther as well as John VII of Ravenna.
[5] Theotgaud, who is sometimes regarded as a mere tool of Gunther, returned to his diocese to perform his episcopal and pastoral functions for Easter despite the ban.
On 31 October 867, Nicholas sent letters to Louis the German and all the bishops of East Francia announcing that Gunther and Theotgaud were guilty of seven offences and therefore deposed from their sees and never eligible to hold ecclesiastical office again.
Theotgaud was now freed from the ban, but Gunther remained excommunicated until the summer of 869, when, after a public retraction, he was admitted by the pope to lay communion at Monte Cassino.