Lateran (II.) in 1139, composed of nearly 1000 bishops, under the presidency of Pope Innocent II. It decided on the due election of this pope, and condemned the errors of Peter de Bruys and Arnold of Brescia.
Lateran (III.) in 1179. At this council, with Pope Alexander III. at their head, 302 bishops condemned what they were pleased to call the “errors and impieties” of the Waldenses and Albigenses.
Lateran (IV.) in 1215, composed of 412 bishops, under Innocent III., had for its objects the recovery of the Holy Land, reformation of abuses, and the extirpation of heresy.
Lyons (I.) in 1245, consisting of 140 bishops, was convened for the purpose of promoting the Crusades, restoring ecclesiastical discipline, and dethroning Frederick II., emperor of Germany. It was also decreed at this council that cardinals should wear red hats.
Lyons (II.) in 1274. There were 500 bishops and about 1000 inferior clergy present. Its principal object was the reunion of the Greek and Latin Churches.
Vienne in Gaul, 1311, consisting of 300 bishops, who were convoked to suppress the Knights Templars, condemn those who were accused of heresy, and assist the Christians in Palestine.
Constance, in 1414–1418. The German emperor, the pope, 20 princes, 140 counts, more than 20 cardinals, 7 patriarchs, 20 archbishops, 91 bishops, 600 other clerical dignitaries, and about 4000 priests, were present at this celebrated ecclesiastical assembly, which was occasioned by the divisions and contests that had arisen about the affairs of the Church. From 1305–1377, the popes had resided at Avignon; but in 1378, Gregory XI. removed the papal seat back to Rome: after his death, the French and Italian cardinals could not agree upon a successor, and so each party chose its own candidate. This led to a schism, which lasted forty years. Indeed, when the emperor Sigismund ascended the throne, in 1411, there were three popes, each of whom had anathematized the two others. To put an end to these disorders, and to stop the diffusion of the doctrines of Huss, Sigismund went in person to Italy, France, Spain, and England, and (as the emperor Maximilian I. used to say, in jest, performing the part of the beadle of the Roman empire) summoned a general council. The pretended heresies of Wickliff and Huss were here condemned, and the latter, notwithstanding the assurances of safety given him by the emperor, was burnt, July 7, 1415; and his friend and companion, Jerome of Prague, met with the same fate, May 30, 1416. The three popes were formally deposed, and Martin V. was legally chosen to the chair of St. Peter.
Basle, 1431, under the presidency of the cardinal legate Juliano Cæsarini of St. Angelo, after holding not fewer than forty-five sessions, terminated its labours, May 16, 1443. Its objects, which were partly attained, were to extirpate heresies, limit the power of the pope, effect a reformation of the clergy, and consolidate the interests of the Church. Its decrees are not admitted into any of the Roman collections, and are considered of no authority by the Roman lawyers. They are, however, recognised in points of canon law in France and Germany; and though some later concordats have modified the application of them, they have never been formally and entirely annulled.
Florence, 1439–1442. It was composed of 141 bishops, the patriarch of Constantinople, and the legates of the patriarchs of Alexandria, Antioch, and Jerusalem. It effected a renunciation of schism on the part of the Greeks, and an abjuration of heresy on the part of the Armenians.
Lateran (V.) in 1512, convened by Pope Julius II., to oppose another held by nine cardinals of high rank the year before at Pisa, with a view to bridle his wild animosity, turbulence, and contumacy. It declared that council schismatic, abolished the Pragmatic Sanction, and strengthened the power of the Roman see.