The Catholic Baptism of Saint Constantine The Great, by Pope Sylvester I
Constantine The Great, received The Catholic Baptism from Pope Sylvester I. This is attested to in the Roman Catholic Martyrology on December 31 of each year, under the heading of Saint Sylvester I Pope. "Romæ natális sancti Silvéstri Primi, Papæ et Confessóris; qui Magnum Constantínum Imperatórem baptizávit, et Nicænam confirmávit Synodum, ac, multis áliis rebus sanctíssime gestis, quiévit in pace. At Rome, the birthday of Pope St. Sylvester I, confessor, who baptized Emperor Constantine the Great, and confirmed the council of Nicaea. After performing many other holy deeds, he rested in peace." from http://www.breviary.mobi/martyrology/mart12/mart1231.htm
The mother of Saint Constantine was The Empress Saint Helena, who founded The Holy Cross. "Helena (empress) - Wikipedia, the free encyclopedia en.wikipedia.org/wiki/Helena_(Empress)
Disputing the "baptism" at death, by the Arian heretic Eusebius, of the Great Constantine I, Holy Catholic Emperor: He was baptized during life by Saint Pope Sylvester I. Nota Bene: In many of the Wikipedia articles on Saint Constantine The Great, it is erroneously stated that he was baptized at death by an Arian heretic. The Holy Catholic Church celebrates his feastday, along with his mother, Saint Helena, each year, on the 21st day of the fifth month.
Emperor Constantine the Great was baptized by Pope St. Sylvester I. See The Roman and British Martyrology. Publisher: O’Neill and Duggan, Dublin, 1846. 31st December, p. 427: "In Rome, the feast of St. Sylvester, pope, who baptized the Emperor Constantine, and confirmed the decrees of the Council of Nice." Also see The Roman Breviary, translated out of Latin into English by John, Marquess of Bute, K. T. Publisher: William Blackwood and Sons, Edinburgh and London, 1908. Vol. 1, Winter, Dec. 31: Pope St. Sylvester, Matins: Second Nocturn: Fourth Lesson, p. 307: "Silvester [I.] was a Roman by birth, and his father’s name was Rufinus. ... In his thirtieth year he was ordained Priest of the Holy Roman Church by Pope Marcellinus. In the discharge of his duties he became a model for all the clergy, and, after the death of Melchiades, he succeeded him on the Papal throne, [in the year of our Lord 314,] during the reign of Constantine, who had already by public decree proclaimed peace to the Church of Christ. ...It was Silvester who caused him [Emperor Constantine] to recognise the images of the Apostles, administered to him holy Baptism, and cleansed him from the leprosy..." and The Roman Breviary, translated out of Latin into English by John, Marquess of Bute, K. T. Publisher: William Blackwood and Sons, Edinburgh and London, 1908. Vol. 2, Summer, November 9: Dedication of the Cathedral Church of the Most Holy Saviour, at Rome, Matins: Second Nocturn: Fifth Lesson, pp. 1346-47: "But when the Emperor Constantine had by the Sacrament of Baptism received health both of body and soul, then first in a law by him published was it allowed to the Christians throughout the whole world to build Churches, to the which holy building he exhorted them by his example as well as by his decree. He dedicated in his own Lateran Palace a Church to the Saviour, and built hard by it a Cathedral in the name of St. John the Baptist, upon the place where he had been baptized by holy Silvester and cleansed from his leprosy." Also see the Liber Pontificalis for December 31 and the inscription on a side of the St. John Lateran obelisk at Rome which reads, "CONSTANTINUS PER CRUCEM VICTOR AS SILVESTRO HIC BAPTIZATUS CRUCIS GLORIAM PROPAGAVIT." (Della Letteratura Italiana, by Cesare Cantù. Publisher: Presso L’Unione Tipografico-Editrice, Torino, 1856. Chap. 5, §4, p. 338)CatholicCrusade2013 22:52, 3 February 2015 (UTC) —
I would also like to add another source from the Chronologies of Theophanes the Confessor: Chronographia of Theophanis, ex recensione Ioannis Classeni. Publisher: Bonnae IMPENSIS ED. WEBERI, 1839. Volume 1, p. 25: "A.C. 314 Hoc anno, ut nonnulli referunt, magnus Constantinus cum Crispo filio Romae a Sylvestro baptizatus est..." (Translation: A.C. 314 This year, some relate, the great Constantine, with his son Crispus, was baptized by Sylvester at Rome.) CatholicCrusade2013 23:28, 3 February 2015 (UTC)