III. Anatolius is requested to co-operate loyally with Leo's delegates.
But concerning the address presented to us by your clergy, beloved, there is no need to put my sentiments into a letter: it is sufficient to entrust all to my delegates, whose words shall carefully instruct you on every point. And so, dearest brother, do you endeavour with these brethren whom we have chosen as suitable agents in so great a matter faithfully and effectually to carry out what is agreeable to the Church of God: especially as the very nature of the case, and the promise of Divine aid incite you, and our most gracious princes show such holy faith, such religious devotion, that we find in them not only the general sympathy of Christians, but even that of the priesthood.
Who assuredly in accordance with that piety, whereby they boast themselves to be servants of God, will receive all your suggestions for the benefit of the Catholic Faith in a worthy spirit, so that by their aid also the peace of Christendom can be restored and wicked error destroyed. And if on any points more advice is needed, let word be quickly sent to us, that after investigating the nature of the case, we may carefully prescribe the rightful measures. Dated 9th of June in the consulship of the illustrious Adelfius (451).
Source: Letters (New Advent)