Letter 1
Hilary, bishop of Rome, to Leontius, bishop of Arles, greetings.
The request you have made for a formal confirmation of your metropolitan authority over the provinces subject to the see of Arles is one we grant willingly, because a clear and recognized structure of authority is essential to the proper functioning of the church in those provinces.
The authority of the bishop of Arles as metropolitan [the senior bishop of a group of dioceses, responsible for supervising episcopal elections and exercising appellate jurisdiction] derives from the long tradition established by our predecessors, confirmed by the canons of the relevant councils, and sustained by the quality of leadership that the bishops of Arles have provided over many decades. We confirm that authority in its full scope as it has been understood and exercised.
Specifically: episcopal elections in the provinces under your metropolitan authority are to be conducted with your supervision and confirmation. Appeals from the decisions of bishops in your province may be made to you before being directed to this apostolic see. Questions of canonical discipline that cannot be resolved within a province are to be referred through you to us.
We ask in return for what we always ask of those who exercise authority in the church: that it be exercised in the service of the people entrusted to your care, and with the pastoral heart that the Lord requires of those who feed his sheep.
Hilary, bishop of Rome
Modern English rendering for readability. See the 19th-century translation or original Latin/Greek for scholarly use.