Galla Placidia Augusta

“…the synod held at Ephesus (the Robber synod) is alleged to have rather stirred up hatred and contention, intimidating by the presence of soldiers, Flavianus, the bishop of Constantinople, because he had sent an appeal to the Apostolic See, and to all the bishops of these parts by the hands of those who had been deputed to attend the Synod by the most reverend bishop of Rome, who have been always wont to attend, most sacred Lord and Son and adored King, in accordance with the provisions of their Nicene Synod. For this cause we pray your clemency to oppose such disturbances with the Truth, and to order the faith of the catholic religion to be preserved without spot, in order that according to the standard and decision of the Apostolic See, wherein assuredly He first adorned primacy, who was deemed worthy to receive the Keys of heaven: for it becomes us in all things to maintain the respect due to this great city which is the mistress of all the earth; and this too we must most carefully provide that what in former times our house guarded seem not in our day to be infringed, and that by the present example schisms be not advanced either between the bishops of the most holy churches” (Letter from Galla Placidia Augusta, the wife of the Western Roman Emperor, Constantius III, to her son Theodosius I, the Eastern Emperor; preserved in Epistle 56 of St. Pope Leo the Great).