Pierre d'Ailly (1350 - 1420) was a French theologian and cardinal of the Catholic Church. Events 29 August - An English fleet personally commanded by King Edward III defeats a Spanish fleet in the battle of Les Espagnols sur Mer. ... Events May 21 - Treaty of Troyes. ... Theology is reasoned discourse concerning God (Greek θεος, theos, God, + λογος, logos, word or reason). It also refers to the study of other religious topics. ... A cardinal is a senior ecclesiastical official in the Roman Catholic Church, ranking just below the Pope and appointed by him as a member of the College of Cardinals during a consistory. ... The Roman Catholic Church believes its founding was based on Jesus appointment of Saint Peter as the primary church leader, later Bishop of Rome. ...

He was born in Compiègne. He was chancellor of the University of Paris from 1385 to 1395. He was involved in the effort to end the Great Schism by means of an ecumenical council and participated in both the Council of Pisa (1409) and the Council of Constance (1414-1418) which condemned the Bohemian reformer Jan Hus. He was a lifelong friend and mentor to Jean Gerson. Compiègne is a commune in the Oise département of France, of which it is a sous-préfecture. ... The Sorbonne, Paris, in a 17th century engraving The Sorbonne today, from the same point of view The Sorbonne is frequently used in ordinary parlance as synonymous with the faculty of theology of Paris or the University of Paris in its entirety. ... Events August 14 - Battle of Aljubarrota between the Portuguese under John I of Portugal and the Castilians, under John I of Castile. ... Events End of reign of Hungary by Capet-Anjou family. ... The Western Schism or Papal Schism was a split within the Catholic Church in 1378. ... In Catholicism and Eastern Orthodoxy, an ecumenical council or general council is a meeting of the bishops of the whole church convened to discuss and settle matters of Church doctrine and practice. ... This article incorporates text from the public domain Catholic Encyclopedia Preliminaries The Great Schism of the West had lasted thirty years (since 1378), and none of the means employed to bring it to an end had been successful. ... Events January 1 - The Welsh surrender Harlech Castle to the English. ... The Council of Constance was an ecumenical council of the Catholic Church, called by the Emperor Sigismund, a supporter of Antipope John XXIII, the pope recently elected at Pisa. ... Events Council of Constance begins. ... Events May 19 - Capture of Paris by John, Duke of Burgundy September - Beginning of English Siege of Rouen Mircea the Old, ruler of Wallachia dies and is succeeded by Vlad I Uzurpatorul. ... Bohemia This article is about the historical region in central Europe; for other uses, see Bohemia (disambiguation). ... Jan Hus, born circa 1369 in Husinec, Bohemia (now Czech Republic) was a Bohemian religious thinker and reformer. ... Jean de Gerson Jean Charlier de Gerson (December 14, 1363 – July 12, 1429), French scholar and divine, chancellor of the university of Paris, a guiding light of the conciliar movement and the one of most the prominent theologians at the Council of Constance, was born at the village of Gerson...

D'Ailly's Imago Mundi, a work of cosmography, influenced Christopher Columbus in his estimates of the size of world land-mass. Christopher Columbus (conjectural image by Sebastiano del Piombo). ...