Ambrosius
Martyrological notice
The historical Roman Martyrology commemorates Ambrosius on 4 April. The Latin notice identifies the record as bishop and confessor. The source places the commemoration at Mediolani.
Historical martyrology witness · Martyrologium Romanum (Latin historical edition)
Mediolani depositio sancti Ambrosii Episcopi, Confessoris et Ecclesiae Doctoris; cujus studio, inter cetera doctrinae et miraculorum insignia, tempore Arianae perfidiae, tota fere Italia ad catholicam fidem conversa est. Ipsius tamen festivitas septimo Idus Decembris potissimum recolitur, quo die Episcopus Mediolanensis ordinatus est.