Leo to Theodosius Augustus.
On receiving your clemency's letter, I perceived that the universal Church has much cause for joy, that you will have the Christian Faith, whereby the Divine Trinity is honoured and worshipped, to be different or out of harmony with itself in nothing. For what more effectual support can be given to human affairs in calling upon God's mercy than when one thanksgiving, and the sacrifice of one confession is offered to His majesty by all. Wherein the devotions of the priests and all the faithful will reach at last their completeness, if in what was done for our redemption by God the Word, the only Son of God, nothing else be believed than what He Himself ordered to be preached and believed. Wherefore although every consideration prevents my attendance on the day which your piety has fixed for the councils of bishops : for there are no precedents for such a thing, and the needs of the times do not allow me to leave the city, especially as the point of Faith at issue is so clear, that it would have been more reasonable to abstain from proclaiming a synod: yet as far as the Lord vouchsafes to help me, I have bestowed my zeal upon obeying your clemency's commands, by appointing my brethren who are competent to act as the case requires in removing offenses, and who can represent me: because no question has arisen on which there can or ought to be any doubt. Dated 21st of June, in the consulship of the illustrious Asturius and Protogenes, (449).
Source. Translated by Charles Lett Feltoe. From Nicene and Post-Nicene Fathers, Second Series, Vol. 12. Edited by Philip Schaff and Henry Wace. (Buffalo, NY: Christian Literature Publishing Co., 1895.) Revised and edited for New Advent by Kevin Knight. <http://www.newadvent.org/fathers/3604037.htm>.