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 is here 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 397 being already very advanced in age. No source calls Simplicianus explicitely a presbyter, and that he was one is inferred from the indirect evidence.