Felix was born about the year 247 and became bishop of Thibiuca (also called Tubzak or Tibiuca), a town near Carthage in Proconsular Africa, in the present-day region of Tunisia. In 303, when the emperor Diocletian issued edicts ordering the surrender and destruction of the Christian Scriptures and the sacrifice to the gods, the local magistrate Magnillian (Magnilianus) summoned the clergy of Thibiuca. A priest and two readers were first brought before him and excused themselves by saying that the sacred books were in the keeping of their bishop.
The next day Felix, returning from Carthage, was confronted by an officer of Magnillian who demanded: "Give me whatever books and parchments you have." Felix acknowledged that he possessed the Scriptures yet firmly refused to hand them over, declaring that he would rather be burned himself than allow the divine writings to be burned, and that he must obey God rather than the emperors. Magnillian granted him three days for reflection. Finding him unchanged in resolve, the magistrate bound him and sent him to the proconsul Anulinus at Carthage.
There Felix was cast into prison. After further hearings in which he repeated his refusal, he was confined in the harshest part of the jail. Sixteen days later he was brought again before the tribunal and ordered transferred to the prefect. According to one tradition he was then conveyed under chains from place to place by ship in an attempt to bring him before the emperors. Another account places the final scene at Carthage itself. In either case the sentence was death by the sword.
On the day of his martyrdom—traditionally 15 July 303—Felix, then fifty-six years of age, is said to have cried aloud: "Thanks be to God, my God. Fifty-six years have I lived in this world; I have kept virginity, I have observed the Gospel, I have preached the faith and the truth. Lord Jesus Christ, God of heaven and earth, I bow my head to be sacrificed to You who live forever; may You be praised and exalted through all ages. Amen." He was beheaded together with Audactus, Fortunatus, Januarius, and Septimus, who may have been deacons. Their bodies were buried in the basilica of Saint Faustus at Carthage, renowned for the tombs of many African martyrs.
A later tradition, arising after relics of Felix reached Venosa in Apulia, held that he had been exiled there and suffered martyrdom at Venosa rather than at Carthage. Because of this cult he was long honored as patron—and is still co-patron—of Venosa. The Roman Martyrology commemorates him on 15 July, the day of his heavenly birthday. The Church has always venerated him as a saint from time immemorial.
May Saint Felix of Thibiuca obtain for us the courage to treasure the Word of God above every human threat, and may we imitate today his unwavering fidelity.