Aeterna Dei Sapientia §20

²⁰ Whether or not this canon was inserted in defiance of the protests of the papal legates, or to win the favor of the Byzantine Emperor, is not clear. To St. Leo, it appeared to undermine the prerogatives of other more ancient and more illustrious churches, prerogatives which had been recognized by the Fathers of the Council of Nicea. He also saw it as detracting somewhat from the authority of the Apostolic See itself. His misgivings were occasioned not so much by the wording of the twenty-eighth canon as by the policies of those who framed it.