A number of significant councils of the Latin Church were held at Aachen (also known in French as Aix-la-Chapelle) in the early Middle Ages.
In the mixed council of 798, Charlemagne proclaimed a capitulary of eighty-one chapters, largely a repetition of earlier ecclesiastical legislation, that was accepted by the clergy and acquired canonical authority.
At the council of 799, after a discussion of six days Felix (bishop of Urgell) in Spain, avowed himself overcome by Alcuin and withdrew his theory of Adoptionism.
The synod of 836 was largely attended and devoted itself to the restoration of ecclesiastical discipline that had been affected by the civil wars between Louis the Pious and his sons.
[7] In 1166 took place the schismatic council, approved by the Antipope Paschal III, in which was decreed the canonization of Charlemagne, that was solemnly celebrated 29 December of that year.