Justina was an Arian, and the imperial court at Milan pitted itself against the Catholics, under the famous Ambrose, bishop of that city.
The germ of this dealing with a major causa may be found in the practice of the Arian emperors in the 4th century.
He is chiefly known by the part which he took in the Arian controversy.
Justin had, no doubt, special reasons for wishing to see an end to the reign of Theodoric. Justin was orthodox, Theodoric was an Arian.
Three of them express in the strongest language the orthodox faith of the church in opposition to the Arian heresy, and these three put in unmistakable language the procession of the Holy Spirit from both Father and Son.