The persecutions ended in 313 when the Emperors Constantine I and Licinius issued the Edict of Milan which proclaimed the religious toleration in the Roman Empire.

Among its bishops should be named Eustorgius I and Dionysius, who firmly opposed apostasy imposed by the Roman Emperor Constantius II.

Among his successors, Simplicianus, Senator and Dacius (530-52), who lived almost always in exile at Constantinople on account of the Gothic War.

The Schism of the Three Chapters guaranteed autonomy of the Milanese Church for 38 years, since the Lombards were enemies of the Byzantines.

As the power of the burghers grew, that of the archbishops waned, and with it the imperial authority which the prelate represented, and from the 12th century Milan became a Guelph town that fought the Emperor.

The church of Milan was governed from 1979 to 2002 by Cardinal Carlo Maria Martini, who had been a favorite of the Catholic left.

Archbishop Delpini is assisted by four Auxiliary Bishops: Erminio De Scalzi, Luigi Stucchi, Franco Agnesi, and Paolo Martinelli.