Council of Aachen
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.
At the council held in 809, the Frankish Church adopted the filioque addition in the Creed (which contributed to the East–West Schism), although Pope Leo III refused to recognize it as valid (and the Church of Rome did not accept this addition until 1014).
In the Synods of Aachen (816–819), clerical and monastic discipline was the chief issue. The council of 816 established the Rule of Aix which was made obligatory on all establishments of canons and canonesses. The later councils imposed a new revision of the Rule of Saint Benedict on the monks of the Benedictine Order by Benedict of Aniane. A list of monasteries and the services to the crown that they owed following these councils can be found in the Notitia de servitio monasteriorum. 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.
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