Pope Leo I in the context of "Council of Toledo of 447"

Patriarch of the West (Latin: patriarcha occidentis) is one of the official titles of the bishop of Rome as patriarch and highest authority of the Latin Church.

A pope is the Bishop of Rome and the leader of the Catholic Church. Approximately 100 papal tombs are at least partially extant, representing fewer than half of the 266 deceased popes, from Saint Peter to Pope Francis.

For the first few centuries in particular, little is known of the popes and their tombs, and available information is often contradictory. As with other religious relics, multiple sites claim to house the same tomb. Furthermore, many papal tombs that recycled sarcophagi and other materials from earlier tombs were later recycled for their valuable materials or combined with other monuments. For example, the tomb of Pope Leo I was combined with Leos II, III, and IV circa 855, and then removed in the seventeenth century and placed under his own altar, below Alessandro Algardi's relief, Fuga d'Attila. The style of papal tombs has evolved considerably throughout history, tracking trends in the development of church monuments. Notable papal tombs have been commissioned from sculptors such as Michelangelo and Gian Lorenzo Bernini.

The sack of Rome in 455 was carried out by the Vandals led by their king Gaiseric.

A 442 treaty between the Western Roman Empire and Vandal Kingdom included a marriage of state between the daughter of Roman Emperor Valentinian III and the son of Gaiseric. Valentinian's successor Petronius Maximus violated the treaty by marrying his son to Valentinian's daughter, and Gaiseric retaliated with an invasion of Italy. Maximus did not organise a defence of Rome and was lynched by a Roman mob while trying to escape the city. Pope Leo I convinced Gaiseric to avoid the use of violence against residents of the city. The Vandals looted Rome for two weeks, causing widespread destruction to the city, stripping it of most of its valuables, and taking some residents as slaves. Maximus' successor Avitus had little support which led to the outbreak of the Roman civil war of 456.

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 by the miaphysite churches, who view it as a valid continuation of the First Council of Ephesus if not an ecumenical council in its own right. The Second Council of Ephesus was explicitly repudiated by the next council, the Council of Chalcedon of 451. The Council of Chalcedon is recognized as the fourth ecumenical council by Chalcedonian Christians, and the Second Council of Ephesus was named the Latrocinium ("Robber Synod") 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.

Both this council and that at Chalcedon dealt primarily with Christology, the study of the nature of Christ. Both councils affirmed the doctrine of the hypostatic union and upheld the orthodox Christian doctrine that Jesus Christ is both fully God and fully man. The Second Council of Ephesus decreed the formula of Cyril of Alexandria, stating that Christ is one incarnate nature [mia physis] (a qualitative description of the union of divinity and humanity), fully human and fully God, united without separation, without confusion, without mixture and without alteration. The Council of Chalcedon decreed that in Christ two natures exist, "a divine nature [physis] and a human nature [physis], united in one person [hypostasis], with neither division nor confusion".

Pope Gregory I (Latin: Gregorius I; Gregorio I; c. 540 – 12 March 604), commonly known as Saint Gregory the Great (Latin: Sanctus Gregorius Magnus; Italian: San Gregorio Magno), was the 64th Bishop of Rome from 3 September 590 until his death on 12 March 604. He is known for instituting the first recorded large-scale mission from Rome, the Gregorian mission, to convert the then largely pagan Anglo-Saxons to Christianity. Gregory is also well known for his writings, which were more prolific than those of any of the previous popes. The epithet Saint Gregory the Dialogist has been attached to him in Eastern Christianity because of his Dialogues. English translations of Eastern texts sometimes list him as Gregory "Dialogos" from the Greek διάλογος (dialogos, conversation), or the Anglo-Latinate equivalent "Dialogus". He is the second of the three Popes listed in the Annuario Pontificio with the title "the Great", alongside Popes Leo I and Nicholas I.

A Roman senator's son, and himself the prefect of Rome at 30, Gregory lived in a monastery that he established on his family estate before becoming a papal ambassador and then pope. Before becoming Pope, he challenged the theological views of Patriarch Eutychius of Constantinople before the emperor Tiberius II. Although he was the first pope from a monastic background, his prior political experiences may have helped him to be a talented administrator. During his papacy, his administration greatly surpassed that of the emperors Maurice and Theodosius in improving the welfare of the people of Rome. Gregory regained papal authority in Spain and France and sent missionaries to England, including Augustine of Canterbury and Paulinus of York. The realignment of barbarian allegiance to Rome from their Arian Christian alliances shaped medieval Europe. Gregory saw Franks, Lombards, and Visigoths align with Rome in religion. He also combated the Donatist heresy, popular particularly in North Africa at the time.

Flavius Aetius (also spelled Aëtius; Latin: [aːˈɛtiʊs]; c. 390 – 21 September 454) was a Roman general and statesman of the closing period of the Western Roman Empire. He was a military commander and the most influential man in the Empire for two decades (433–454). He managed policy in regard to the attacks of barbarian federates settled throughout the West. Notably, he mustered a large Roman and allied (foederati) army in the Battle of the Catalaunian Plains, ending an invasion of Gaul by Attila in 451, though the Hun and his subjugated allies still managed to invade Italy the following year, an incursion best remembered for the Sack of Aquileia and the intercession of Pope Leo I. In 454, he was assassinated by the emperor Valentinian III.

Aetius has often been called the "Last of the Romans". Edward Gibbon refers to him as "the man universally celebrated as the terror of Barbarians and the support of the Republic" for his victory at the Catalaunian Plains. J.B. Bury notes, "That he was the one prop and stay of the Western Empire during his life time was the unanimous verdict of his contemporaries."

Valentinian III (Latin: Placidus Valentinianus; 2 July 419 – 16 March 455) was Roman emperor in the West from 425 to 455. Starting in childhood, his reign over the Roman Empire was one of the longest, but was dominated by civil wars among powerful generals and the barbarian invasions. He was the youngest sole emperor in the Western Roman Empire (aged 6).

He was the son of Galla Placidia and Constantius III, and as the great-grandson of Valentinian I (r. 364–375) he was the last emperor of the Valentinianic dynasty. As a grandson of Theodosius I (r. 379–395), Valentinian was also a member of the Theodosian dynasty, to which his wife, Licinia Eudoxia, also belonged. A year before assuming the rank of augustus, Valentinian was given the imperial rank of caesar by his half-cousin and co-emperor Theodosius II (r. 402–450). The augusta Galla Placidia had great influence during her son's rule, as did the military commander Flavius Aetius, who defended the western empire against Germanic and Hunnic invasions. Attila the Hun repeatedly menaced Valentinian's domains, being repulsed by a coalition under Aetius's leadership at the Battle of the Catalaunian Plains and calling off a subsequent invasion after negotiations led by Pope Leo I.

Pope Leo is the name of fourteen heads of the Catholic Church:

• Pope Leo I (the Great; saint; 440–461)
• Pope Leo II (saint; 682–683)
• Pope Leo III (saint; 795–816)
• Pope Leo IV (saint; 847–855)
• Pope Leo V (903)
• Pope Leo VI (928–929)
• Pope Leo VII (936–939)
• Pope Leo VIII (964–965)
• Pope Leo IX (saint; 1049–1054)
• Pope Leo X (1513–1521)
• Pope Leo XI (1605)
• Pope Leo XII (1823–1829)
• Pope Leo XIII (1878–1903)
• Pope Leo XIV (2025–present)