Bretannionis
Martyrological notice
The historical Roman Martyrology commemorates Bretannionis on 25 January. The Latin notice identifies the record as bishop. The source places the commemoration at Tomis, in Scythia.
Historical martyrology witness · Martyrologium Romanum (Latin historical edition)
Tomis, in Scythia, sancti Bretannionis Episcopi, qui mira sanctitate et catholicae fidei zelo, sub Ariano Imperatore Valente, cui fortiter restitit, in Ecclesia floruit.