Secundinus the name of two persons in the early Christian Church.
1. A Manichaean of Africa, who wrote against Augustine because of his departure from that heresy. Augustine replied to him, under date of about A.D. 405, in the tract Contra Secundinum Manichoeum, lib. 1, showing why he had embraced orthodox views, and confuting the Manichaeans from the letter of his opponent (Migne, Patrologie, 43, Op. August. p. 578).
2. A son of the Lombard Restitutus and Dareca, a sister of St. Patrick. He lived in Ireland from A.D. 439, and died at the age of seventy-five, in 459. Secundinus was bishop of Domnach, and composed an ode on St. Patrick during the life of the latter, which was long on the lips of the Irish. It is given in Migne (Patrologie, 53, 838). Immediately after having composed the above, ode, he died, thus verifying a prediction of St. Patrick. He was buried at Domnach (Acta Sanctorum, March 17, p. 523 sq., in the life of St. Patrick.