5 surviving letters between Constantius and Sidonius Apollinaris, spanning 467-473 AD.
SIDONIUS TO HIS DEAR CONSTANTIUS, GREETINGS
To Constantius [the final letter of Sidonius's collected correspondence].
To Constantius [Sidonius's literary executor and the dedicatee of the first eight books of letters].
With you it began; with you it shall end.