Background
Mercurinus was the foster-son of Ulfilas (Wulfila), the "apostle to the Goths".
Mercurinus was the foster-son of Ulfilas (Wulfila), the "apostle to the Goths".
In Milan, seat of the Western Imperial court, Nicene and Arian controversy flared high In 386, Auxentius challenged Ambrose to a public disputation, in which the judges were to be the court favourites of the Arian empress. He also demanded for the Arians the use of the Basilica Portiana.
Ambrose"s refusal to surrender this church brought about a siege of the edifice, in which Ambrose and a multitude of his faithful Milanese had shut themselves up.
The empress eventually abandoned her favourite and made peace with Ambrose. He wrote an account of the life and death of Ulfilas that the Arian bishop Maximinus included (383) in a work directed against Saint Ambrose and the Synod of Aquileia, 381.
This favourite of Empress Justina was the anti-bishop set up in Milan by the Arians on the occasion of the election of Ambrose. The Letter of Auxentius (ca 400) was preserved in the margins of a manuscript of De fide of Ambrose.