It is unclear whether Bishop Passivus was the actual father of Demetrianus and Valerianus (and, hence, that they were brothers), or whether Gregory had a spiritual relation in mind. It might be telling that in a letter to Passivus sent at the same time as this one (9.58 ), Gregory does not refer to Valerianus (if this is the same Valerianus, see below) as Passivus' son. Moreover, it is difficult to say why Valerianus and Demetrianus would need confirmation that they do not owe anything to the diocese of Fermo if their own father was the bishop (unless they anticipated that the future successor of Passivus might not be as indulgent).
It is equally uncertain whether the notarius ecclesiae Valerianus of Fermo in letters 9.58  and 9.59  is the same person as the addressee of this letter.
There is also a small possibility that this Valerianus should be identified with the presbyter Valerianus who attempted to ransom the captives in Cyrenaica with Gregory's support in AD 592 .