Baring-Gould’s sources: Roman Martyrology. Venerated at Mainz and Altino. Authority:— The purely apocryphal legend in the Mainz Breviary.] S. Theonestus, Bishop of Philippi in Macedonia, having become odious to the Vandal king Huneric, in North Africa, was banished by him with many other bishops. But how Huneric had anything to do with Philippi is not obvious. He came to Rome with his companions Alban, Ursus, and Thabrathaam. The Pope gave them a commission to evangelize the Germans, and they preached at Augsburg, where S. Ursus was martyred. The rest pushed on to Mainz, where S. Alban fell a victim to his zeal. Theonestus and his other companion were exposed by the S. Talarican.

Arians [followers of Arius, who taught that the Son is a created being, not fully God] of Mainz in a boat without oars or sails, and which they had scuttled, on the Rhine. But they were miraculously preserved, got ashore, and traversing Gaul [roughly modern France and Belgium] preached everywhere till they reached Italy, and there Theonestus and Thabrathaam were arrested and executed. There is probably not a particle of historic truth in this story.