January 27, 398: John Chrysostom, the greatest preacher of his age, is consecrated bishop of Constantinople (see issue 44: John Chrysostom).
January 27, 417: Pelagius, a British monk, is excommunicated for heresy. He was condemned for denying original sin and claiming that men could become righteous purely by the exercise of free will. (see issue 51: Heresy in the Early Church).
January 27, 1302: On a trumped-up charge of hostility to the church and corrupt practices, Dante Alighieri is fined heavily and perpetually excluded from political office (he was a chief magistrate). Further condemned in March and driven out of Florence in April, Dante began writing The Divine Comedy, an epic poem in which he travels through hell, purgatory, and heaven (see issue 70: Danle Alighieri).
July 5, 1439: Greek Orthodox and Roman Catholics sign the Decree of Union at the Council of Florence, creating an official union between the two churches. Popular sentiment in Constantinople opposed the decree, and when the Turks captured the city, the union ceased. However, the council's definition of doctrine and its principles of church union (unity of faith, diversity of rite) have proved useful in subsequent church talks (see issue 54: Eastern Orthodoxy).