Question: In which year did the reign of this emperor, who convoked the Second Council of Constantinople, end?

Context articles: Plato of Sakkoudion
Maximin of Trier
Sixth Council of Toledo
Second Council of Lyon
İslamköy, Kahta
Maximus II of Antioch
Second Council of Constantinople
Council of Mantua (1459)
Justinian I
Second Council of Ephesus

Venerable Platon the Studite, also Plato of Sakkoudion (), probably Constantinople, ca. 735 – Constantinople, 4 April 814, was a Byzantine minor official who became a monk in 759.
 After refusing the metropolitan see of Nicomedia or the headship of a monastery in Constantinople, in 783 he founded the monastery of Sakkoudion on Mount Olympus in Bithynia, of which he became the first abbot.
 He is notable, along with his nephew Theodore Stoudites, for his iconodule stance during the Byzantine Iconoclasm and his participation in the Second Council of Nicaea, and to his firm opposition to the second marriage of Emperor Constantine VI to his niece Theodote (the "Moechian Controversy").
 He was canonized by the Church, and his feast day is April 4.
Saint Maximin (born at Silly near Poitiers; — Poitiers 12 September 346) was the fifth bishop of Trier, according to the list provided by the diocese's website, taking his seat in 341/342.
 Maximin was an opponent of Arianism, and was supported by the courts of Constantine II and Constans, who harboured as an honored guest Athanasius twice during his exile from Alexandria, in 336-37, before he was bishop, and again in 343.
 In the Arian controversy he had begun in the party of Paul I of Constantinople; however, he took part in the synod of Sardica convoked by Pope Julius I (ca. 342), and when four Arian bishops consequently came from Antioch to Trier with the purpose of winning Emperor Constans to their side, Maximinus refused to receive them and induced the emperor to reject their proposals.
The Sixth Council of Toledo was the second council convoked by King Chintila and opened on 9 January 638.
 It was attended by fifty three bishops, including those from Narbonensis who had not participated in the prior council for political reasons.
 The council was thus a reunion of the whole church of Spain (of both Hispania and Gallia).
 Its primary purpose was to reaffirm the decrees of the Fifth Council of 636 and to restore internal peace.
The Second Council of Lyon was the fourteenth ecumenical council of the Catholic Church, convoked on 31 March 1272 and convened in Lyon, France, in 1274.
 Pope Gregory X presided over the council, called to act on a pledge by Byzantine emperor Michael VIII to reunite the Eastern church with the West.
 The council was attended by about 300 bishops, 60 abbots and more than a thousand prelates or their procurators, among whom were the representatives of the universities.
 Due to the great number of attendees, those who had come to Lyon without being specifically summoned were given "leave to depart with the blessing of God" and of the Pope.
 Among others who attended the council were James I of Aragon, the ambassador of the Emperor Michael VIII Palaiologos with members of the Greek clergy and the ambassadors of Abaqa Khan of the Ilkhanate.
 Thomas Aquinas had been summoned to the council, but died en route at Fossanova Abbey.
 Bonaventure was present at the first four sessions, but died at Lyon on 15 July 1274.
 As at the First Council of Lyons Thomas Cantilupe was an English attender and a papal chaplain.
The village corresponds to ancient Alia, which was in the Roman province of Phrygia Pacatiana, whose capital was Laodicea on the Lycus.
 The names of some of the bishops of Alia are known through their participation in church councils: Caius at the Council of Chalcedon (451), Glaucus at the Second Council of Constantinople (553), Leo at the Second Council of Nicaea (787), and Michael and Georgius, the one a supporter of Patriarch Ignatius of Constantinople, the other a supporter of Photius, at the Council of Constantinople (879).
Maximus II was a 5th-century patriarch of Antioch.
 After the deposition of Domnus II by the Second Council of Ephesus, 449, Dioscorus persuaded the emperor Theodosius II to fill the vacancy with one of the clergy of Constantinople.
 Maximus was selected and ordained, in violation of canon law, by Patriarch Anatolius of Constantinople, without the official sanction of the clergy or people of Antioch.
The Second Council of Constantinople is the fifth of the first seven ecumenical councils recognized by both the Eastern Orthodox Church and the Roman Catholic Church.
 It is also recognized by the Old Catholics and others.
 Protestant opinions and recognition of it are varied.
 Some Protestants, such as Calvinists and Lutherans, recognise the first four councils, whereas most High Church Anglicans accept all seven.
 Constantinople II was convoked by the Byzantine Emperor Justinian I under the presidency of Patriarch Eutychius of Constantinople.
 It was held from 5 May to 2 June 553.
 Participants were overwhelmingly Eastern bishops only sixteen Western bishops were present, including nine from Illyricum and seven from Africa, but none from Italy out of the 152 total.
The Council of Mantua of 1459, or Congress of Mantua, was a religious meeting convoked by Pope Pius II, who had been elected to the Papacy in the previous year and was engaged in planning war against the Ottoman Turks, who had taken Constantinople in 1453.
 His call went out to the rulers of Europe, in an agonized plea to turn from internecine warfare to face Christendom's common enemy.
Justinian I ( ; Latin: "Flavius Petrus Sabbatius Iustinianus Augustus" ; Greek: Φλάβιος Πέτρος Σαββάτιος Ἰουστινιανός "Flávios Pétros Sabbátios Ioustinianós" ) ( 482 14 November 565), traditionally known as Justinian the Great and also Saint Justinian the Great in the Eastern Orthodox Church, was the Byzantine (East Roman) emperor from 527 to 565.
 During his reign, Justinian sought to revive the empire's greatness and reconquer the lost western half of the historical Roman Empire.
 Justinian's rule constitutes a distinct epoch in the history of the Later Roman empire, and his reign is marked by the ambitious but only partly realized "renovatio imperii", or "restoration of the Empire".
The Second Council of Ephesus (commonly known as the Robber Council of Ephesus) was a Christological church synod in 449 AD convened by Emperor Theodosius II under the presidency of Pope Dioscorus I of Alexandria.
 It was intended to be an Ecumenical Council, but because of the scandalous nature of the proceedings, canon legalities, and the heterodox nature of the canons and decrees as viewed by the orthodox bishops of East and West (and the later ecumenical councils), it was never accepted as ecumenical.
 It was explicitly repudiated by the fourth and next ecumenical council, the Council of Chalcedon of 451, and named the "Latrocinium", or "Robber Council".