Little is known about the life of Saint Dionysius before his election as Bishop of Milan in 349. Dionysius is believed to have been of Greek origin and a friend of the Roman Emperor Constantius II before his election. The historical period in which Dionysius lived was marked by clashes between Arians and followers of the faith defined at the Council of Nicaea.
In 355, Pope Liberius asked the Emperor to convene a Synod in Milan, held in the new Basilica Nova (or Major Basilica or Saint Thecla). Despite high hopes, the council did not achieve its objectives due to the large presence of Arian bishops and the absence of the defender of the Nicene faith, Eusebius of Vercelli.
Initially, Dionysius seemed ready to follow the Arians in condemning Athanasius of Alexandria, accused not of heresy, but of lese majesty against the Emperor. However, Eusébio’s arrival changed the situation.
Eusebius asked the bishops to immediately sign the Nicene faith. While Eusebius, the papal legate Lucifer of Cagliari and Dionysius signed, the Arian bishop Valenco of Mursia violently destroyed the act of faith. Constantius, unaccustomed to the independence of bishops, moved the synod to his palace and cruelly punished Eusebius, Lucifer and Dionysius, who were all exiled (and also Pope Liberius was subsequently exiled).
Dionysius was exiled to Caesarea in Cappadocia and replaced as bishop of Milan by the Arian Auxentius, appointed by the emperor.
Dionysius died in exile between 360 and 362. A late, historically unfounded tradition associates Dionysius with the Mariani family of Milan. His feast day is celebrated on May 25th. It is believed that in 375 or 376, Saint Ambrose sent a delegation to recover the body of Dionysius and transfer it to Milan.
Today, three parishes in Lombardy are dedicated to Saint Dionysius: San Dionigi in Pratocentenaro in Milan, San Dionigi in Premana and San Dionigi in Carcano de Albavilla.
