DIONISIO, PAPA. – The anonymous author of the Lib. Pont., who reflects the historical mentality of the sixth century, asserts that he came from the monastic class; perhaps he intended to allude to D.’s status as an ascetic. He held the pontificate (according to the conventional chronology) from the consulship of Emiliano and Basso (259) until that of Claudio and Paterno (265). In any event, it is certain that he must have been a pope of the third century. He was buried in the cemetery of Callistus on the Via Appia. His epitaph has not come down to us.
But the pilgrims’ Itineraries of the seventh and eighth centuries call him «papa et martyr». The Lib. Pont. attributes to him an arrangement of the urban ecclesiastical districts: «Hic presbiteris ecclesias dedit et cymiteria et paroecias decessis instituit». Far more important, however, was his intervention in the Trinitarian controversy, prompted by a letter from Dionisio Alessandrino, who opposed the excesses of Sabellian and Modalist doctrines, but in turn fell into the error of an exaggerated distinction between the three divine Persons and a clear subordination of the Son to the Father. D. submitted the letter for examination by a council, and then replied, condemning Modalism as well as those who admitted three separate hypostases and made the Word a creature. In a separate letter D. invited the Alexandrian bishop of the same name to provide explanations. The latter did so by sending a defense that appears to have satisfied the Church of Rome (cf. Eusebio, Historia eccl., VII, 26; Atanasio, De decretis Nic. syn., chaps. 25 and 26, and De sent. Dion., passim).