at the Battle of the Milvian Bridge. Tradition has it that, the night before the battle, Constantine had a vision that he would achieve victory if he fought under the symbol of Christ; accordingly, his soldiers bore on their shields the Chi-Rho sign composed of the first two letters of the Greek word for "Christ" (ΧΡΙΣΤΌΣ). 313–476 313: The Edict of Milan declares the Roman Empire neutral towards religious views, in effect ending the persecution of Christians. 318: Arius condemned and excommunicated by a council convened by Alexander, bishop of Alexandria. 321: Granting the Church the right to hold property, Constantine donates the palace of the Laterani to Pope Miltiades. The Lateran Basilica (Basilica of Our Savior) becomes the episcopal seat of the Bishop of Rome. November 3, 324: Constantine lays the foundations of the new capital of the Roman Empire in Byzantium, later to be known as Constantinople. 323 Pope Sylvester I in his calendar lists Sunday (rather than the Jewish Saturday) as the first day of the week, names it "the Lord's day", and commands church members to keep it as a holy day. 325: The Arian controversy erupts in Alexandria, causing widespread violence and disruptions among Christians. 325: The First Ecumenical Council of Nicaea, convened as a response to the Arian controversy, establishes the Nicene Creed, declaring the belief of orthodox Trinitarian Christians in the Trinity. November 18, 326: Pope Sylvester I consecrates the Basilica of St. Peter built by Constantine the Great over the tomb of the Apostle. 336: Date of the first recorded celebration of Christmas in Rome. 345: Pope Julius I officially sets the date of December 25 for the celebration of the Nativity or Christmas. 360: Julian the Apostate becomes the last non-Christian Roman Emperor. February, 380: Emperor Theodosius I issues an edict, De Fide Catolica, in Thessalonica, published in Constantinople, declaring Catholic Christianity as the state religion of the Roman Empire. 381: First Ecumenical Council of Constantinople. 382: The Council of Rome under Pope Damasus I sets the Canon of the Bible, listing the accepted books of the Old Testament and the New Testament. No others are to be considered scripture. July, 387: Ambrose, bishop of Milan, baptizes Augustine of Hippo, along with his son, Adeodatus, in Milan. 391: The Theodosian decrees outlaw most pagan rituals still practiced in Rome, thereby encouraging much of the population to convert to Christianity. 400: Jerome's