His task was to reorganise the Catholic Church, after the persecutions of Emperor Valerian I, and the edict of toleration by his successor Gallienus.

The pope in Rome called for explanations; a satisfactory response duly arrived back, notwithstanding expostulation about the propriety of all this from some of the Alexandrian Christians.

[1] To rebuild, and to ransom those held captive, Pope Dionysius sent large sums of money to the churches of Cappadocia, devastated by marauding Goths.

Following Emperor Gallienus' edict of toleration, he brought order to the church and helped secure a peace that lasted until 303, some 35 years after his death on 26 December 268.

[1] According to St. Athanasius, Pope St. Dionysius retroactively condemned Arianism far before the First Ecumenical Council of Nicaea on behalf of the entire Church saying, "For Dionysius, Bishop of Rome, having written also against those who said that the Son of God was a creature and a created thing, it is manifest that not now for the first time but from of old the heresy of the Arian adversaries of Christ has been anathematised by all.