The Council of Chalcedon was the fourth ecumenical council of the Christian Church. It was convoked by the Roman emperor Marcian. The council convened in the city of Chalcedon, Bithynia from 8 October to 1 November 451. The council was attended by over 520 bishops or their representatives, making it the largest and best-documented of the first seven ecumenical councils. The principal purpose of the council was to re-assert the teachings of the ecumenical Council of Ephesus against the teachings of Eutyches and Nestorius. Such doctrines viewed Christ's divine and human natures as separate (Nestorianism) or viewed Christ as solely divine (monophysitism).
Pope Alexander II, born Anselm of Baggio, was the head of the Roman Catholic Church and ruler of the Papal States from 1061 to his death in 1073. Born in Milan, Anselm was deeply involved in the Pataria reform movement. Elected according to the terms of his predecessor's bull, In nomine Domini, Anselm's was the first election by the cardinals without the participation of the people and minor clergy of Rome. He also authorized the Norman Conquest of England in 1066.
Pope Boniface I was the bishop of Rome from 28 December 418 to his death on 4 September 422. His election was disputed by the supporters of Eulalius until the dispute was settled by Emperor Honorius. Boniface was active in maintaining church discipline, and he restored certain privileges to the metropolitical sees of Narbonne and Vienne, exempting them from any subjection to the primacy of Arles. He was a contemporary of Augustine of Hippo, who dedicated to him some of his works.
Pope Zosimus was the bishop of Rome from 18 March 417 to his death on 26 December 418. He was born in Mesoraca, Calabria. Zosimus took a decided part in the protracted dispute in Gaul as to the jurisdiction of the See of Arles over that of Vienne, giving energetic decisions in favour of the former, but without settling the controversy. His fractious temper coloured all the controversies in which he took part, in Gaul, Africa and Italy, including Rome, where at his death the clergy were very much divided.
Pope Leo I, also known as Leo the Great, was Bishop of Rome from 29 September 440 until his death.
Pope Fabian was the bishop of Rome from 10 January 236 until his death on 20 January 250, succeeding Anterus. A dove is said to have descended on his head to mark him as the Holy Spirit's unexpected choice to become the next pope. He was succeeded by Cornelius.
Pope Simplicius was the bishop of Rome from 468 to his death. He combated the Eutychian heresy, ended the practice of consecrating bishops only in December, and sought to offset the effects of Germanic invasions.
Pope Hormisdas was the bishop of Rome from 20 July 514 to his death. His papacy was dominated by the Acacian schism, started in 484 by Acacius of Constantinople's efforts to placate the Monophysites. His efforts to resolve this schism were successful, and on 28 March 519, the reunion between Constantinople and Rome was ratified in the cathedral of Constantinople before a large crowd.
The Archbasilica of Saint John Lateran is the Catholic cathedral of the Diocese of Rome in the city of Rome, and serves as the seat of the bishop of Rome, the pope. The archbasilica lies outside of Vatican City proper, which is located approximately four kilometres northwest. Nevertheless, as properties of the Holy See, the archbasilica and its adjoining edifices enjoy an extraterritorial status from Italy, pursuant to the terms of the Lateran Treaty of 1929. Dedicated to the Christ, in honor of John the Baptist and John the Evangelist, the place name, Laterano (Lateran) comes from an ancient Roman family (gens), whose palace (domus) grounds occupied the site; the adjacent Lateran Palace was the primary residence of the pope until the Middle Ages.
Hilary of Arles, also known by his Latin name Hilarius, was a bishop of Arles in Southern France. He is venerated as a saint in the Eastern Orthodox Church and Roman Catholic Church, with 5 May being his feast day.
Flavian, sometimes Flavian I, was Archbishop of Constantinople from 446 to 449. He is venerated as a saint and martyr by the Eastern Orthodox Church and the Catholic Church.
Anatolius was a Patriarch of Constantinople. He is regarded as a saint, by both the Orthodox and Roman Catholic Churches.
Dioscorus I, also known as Dioscorus the Great, was the pope of Alexandria and patriarch of the See of St. Mark who was deposed by the Council of Chalcedon in 451. He was recognized as patriarch by the Coptic Church until his death. He died in Gangra, Paphlagonia, in September 454. He is venerated as a saint by the Coptic and other Oriental Orthodox Churches.
Domnus II was the Patriarch of Antioch between 442 and 449 and a friend of the influential Bishop of Cyrrhus, Saint Theodoret.
Mamertus was the bishop of Vienne in Gaul, venerated as a saint. His primary contribution to ecclesiastical practice was the introduction of litanies prior to Ascension Day as an intercession against earthquakes and other disasters, leading to "Rogation Days." His feast day is the first of the Ice Saints.
The Second Council of Ephesus was a Christological church synod in 449 convened by Emperor Theodosius II under the presidency of Pope Dioscorus I of Alexandria. It was intended to be an ecumenical council, and it is accepted as such by the miaphysite churches but was rejected by Chalcedonian Christians. It was explicitly repudiated by the next council, the Council of Chalcedon of 451, recognised as the fourth ecumenical council by Chalcedonian Christians, and it was named the Latrocinium by Pope Leo I; the Chalcedonian churches, particularly the Roman Catholic and Eastern Orthodox communions, continue to accept this designation, while the Oriental Orthodox repudiate it.
Rusticus of Narbonne was a monk of the Lérins Abbey and bishop of Narbonne and Catholic saint of Gaul, born either at Marseilles or at Narbonne.
Arles in the south of Roman Gaul hosted several councils or synods referred to as Concilium Arelatense in the history of the early Christian church.
Gaul was an important early center of Latin Christianity during late antiquity and the Merovingian period. By the middle of the 3rd century, there were several churches organized in Roman Gaul, and soon after the cessation of persecution, the bishops of the Latin world assembled at Arles in AD 314. The Church of Gaul passed through three crises in the late Roman period, Arianism, Priscillianism and Pelagianism. Under Merovingian rule, a number of "Frankish synods" were held, marking a particularly Germanic development in the Western Church. A model for the following Frankish synods was set by Clovis I, who organized the First Council of Orléans (511).
Constantine the Great's (272–337) relationship with the four Bishops of Rome during his reign is an important component of the history of the Papacy, and more generally the history of the Catholic Church.
