Here, Ambrose's addressee is Simplicianus, most probably the same whom Augustine mentions in the Confessions 8.2 as the pater in accipienda gratia tunc episcopi Ambrosii (). In his letters to Simplicianus, Ambrose always expresses the filial affection, which suggests seniority of Simplicianus. He succeeded Ambrose in the see of Milan in AD 397, being already very advanced in age. No source calls Simplicianus explicitly a presbyter, and that he was one is inferred from the indirect evidence. The present letter is not dated, but it is clearly a continuation of Letter 7  in which, in chapter 3, Ambrose makes reference to his work De Iacob et vita beata written in 386, so the letter must have been composed afterwards.