SECONDIANO, bishop of Singidunum. — In 366 he was still a priest and follower of Ursacius and Valens, as appears from the letter addressed by them to Germinius, bishop of Sirmium (CSEL, 65, p. 180).
After his elevation to the episcopate, he was tried and condemned as an Homoian in 378 at Sirmium, but he appealed to the emperor Gratian, requesting to be judged and heard in a general council, which could only be convened in 381 at Aquileia, under the direction of St Ambrose. Despite his delays, S. was exposed as a condemned heretic.