Lives of the Saints, by Alban Butler, Benziger Bros. ed. [1894], at sacred-texts.com
ST. STEPHEN was by birth a Roman, and, being promoted to holy orders, was made archdeacon under the holy Popes St. Cornelius and St. Lucius. The latter? having suffered martyrdom, St. Stephen was chosen to succeed him, and was elected Pope on the 3d of May, 253. The controversy concerning the rebaptization of heretics gave St. Stephen much trouble. It is the teaching of the Catholic Church, that Baptism given in the name of the three persons of the Blessed Trinity is valid, though it be conferred by a heretic. St. Stephen suffered himself patiently to be traduced as a favorer of heresy in approving heretical baptism, not doubting but those great men who by mistaken zeal were led astray would, when the heat of the dispute had subsided, calmly open their eyes to the truth. Thus by his zeal he preserved the integrity of faith, and by his toleration and forbearance saved many souls. The persecutions becoming violent, he assembled the faithful together in the underground tombs of the martyrs, to celebrate Mass and to exhort them to remain true to Christ. On the 2d of August, 257, while seated in his pontifical chair, he was beheaded by the satellites of the emperor; and the chair is still shown, stained with his blood.