Ioannes 39 was bishop of Thessalonike, vicar of the see of Rome; in 681 he attended the Third Council of Constantinople (the Sixth Ecumenical Council) as a representative (of the pope) and was present at the last nine sessions (sessions ten to eighteen, from 18 March to 16 September 681): Riedinger II 2. 280-822 (= Mansi XI 389-669). In the subscriptions to the statement of the faith, which condemned monotheletism, and to the Council, he is styled Ἰωάννης ἐλέει Θεοῦ ἐπίσκοπος Θεσσαλονίκης καὶ βικάριος τοῦ ἀποστολικοῦ θρόνου Ῥώμης καὶ ληγάτος (Riedinger II 2. 778, lines 17-18 (= Mansi XI 640) reads ληγατάριος): Riedinger II 2. 778, lines 17-18, 822, lines 22-23 (= Mansi XI 640, 669) (the old Latin version printed in Riedinger II 2. 779, line 19, calls him "episcopus Thesalonicae et uicarius apostolicae sedis Romae et legatus". In the lists of those attending each session he is styled Ἰωάννου ἐπισκόπου Θεσσαλονίκης: Riedinger II 2. 280, line 10, 402, line 19, etc. (= Mansi XI 389, 457, etc.). He was among those who subscribed the copy of the definition of the faith sent to the bishop of Rome, signing on behalf of himself and the bishops under him (ὑπὲρ ἐμαυτοῦ καὶ τῆς ὑπ'ἐμὲ συνόδου): Riedinger II 2. 891, lines 5-6 (= Mansi XI 688). Possibly identical with Ioannes 148.

(Publishable link for this person: )