Ambrose was a bishop of Milan from 374 until his death in 397. We have a collection of his letters organized in three parts. The first one consists of 77 letters organized in ten books most probably by Ambrose himself. He published his letters at some point after the death of Theodosius in 395. From this collection, Book 4 is missing, as are some letters of Books 2 and 4. The second part is the group of letters that survived outside the collection (extra collectionem), and the third is a group of letters concerning the council of Aquileia in 381 (together with the acts of this council). For a detailed discussion on the letters and further reading see Liebeschuetz 2010: 27–48 and Nauroy 2016: 146–160.

 

The present letter is not dated and it can only be said that it was written at some point during the episcopacy of Ambrose. Ambrose`s addresee, Iraeneus, is treated with paternal affection. Irenaeus received several letters from Ambrose and is known only from this correspondence. He is never explicitely called a presbyter (or a cleric) and there is a scholarly discussion whether he actually was one - see especially Palanque 1933. That Irenaeus was a lay man is claimed by Paredi 1968: 498 and Zelzer 1978: 15. He is considered a cleric by Mazières 1979 and later by Zelzer 1990: XXI, n. 6. See PCBE, Italie 1, Irenaeus 1.