The treaty ending the war between Constantinople and the Huns is harsher than that of 443; the Eastern Romans have to evacuate a wide belt of territory south of the Danube, and the tribute payable by them is continued, though the rate is not known.

When Marcian abruptly cancels the subsidies to the Huns, the prospect of conquests in the West divert Attila from revenge.

When in 449 a Frankish ruler (name and location unknown) died, Aetius, master of soldiers and the real ruler of the West, had adopted the younger son to secure the Rhine Frontier, and the elder son had fled to the court of Attila.

Attila appears to be on friendly terms with Aetius and his motives for marching into Gaul have not been recorded.

He announces that his objective in the West is the kingdom of the Visigoths, centered on Tolosa (Toulouse), and that he has no quarrel with the Western emperor, Valentinian III.

The historian Jordanes states that Attila was enticed by gifts from the Vandals' king Genseric to wage war on the Visigoths.

At the same time, Genseric would attempt to sow strife between the Visigoths and the Western Roman Empire (Getica 36.184–6).

Other contemporary writers offer different motivations: Honoria, the troublesome sister of the emperor Valentinian III, had been married off to the loyal senator Herculanus a few years before, keeping her in respectable confinement.

In the spring of 450, she had sent a message, together with her engagement ring, to the Hunnic king asking for Attila's help in escaping her confinement.

Though Honoria may not have intended a proposal of marriage, Attila chose to interpret her message as such.

He had accepted, asking for half of the western Empire as dowry.

When Valentinian discovered the plan, only the influence of his mother Galla Placidia had persuaded him to exile, rather than kill, Honoria.

He also wrote to Attila strenuously denying the legitimacy of the supposed marriage proposal.

Attila had sent an emissary to Ravenna to proclaim that Honoria is innocent, that the proposal had been legitimate, and that he will come to claim what is rightfully his.

Armenia, parts of which are now nominally subject to the Eastern Roman emperor, and others to the Sassanians of Persia, is actually controlled by native clan leaders known as “nakharars.

Although these nobles are mostly disunited and divided, they fight together to repel the Sassanians at Avarayr in 451.

Yazdegerd, advancing his pro-Zoroastrian policy, battles an uprising of sixty-six thousand Armenian Christians in the Battle of Avarayr in 451, on the Avarayr Plain.

Yazdegerd defeats the Armenian rebels led by Vartan Mamikonian.

Despite the battle death of Mamikonian, the Armenians consider this battle to have been a moral and religious victory, since Yazdegerd, out of respect for their efforts, allows them to remain Christian.

The anniversary will become a national and religious holiday.

Yazdegerd, having grown suspicious of Christians in the army and the nobility during his eastern campaign, had expelled many of them.

He had then persecuted the Assyrian Christians and, to a much lesser extent, Jews (he publishes a decree abolishing the Sabbath, and orders executions of Jewish leaders, including the Exilarch Mar Nuna).

Marcian, at the urging of Pope Leo, convokes the Christian church’s fourth ecumenical council, the Council of Chalcedon, in 451, primarily to resolve theological disputes about the person of Jesus Christ.

The council formally condemns the so-called Robber Synod and, once again, reaffirms the Nicene Creed.

Repudiating the Monophysite emphasis on the divinity of Christ over his humanity, the council promulgates a dogmatic statement called the "Faith of Chalcedon," which describes Christ as possessing two natures, divine and human, "without confusion, without change, without division," perfectly united in a single person.

The council, like its predecessor at Ephesus, upholds the title “theotokos” as descriptive of Mary.

The council also condemns the practice known as simony (after Simon Magus, who, according to “Acts of the Apostles,” attempted to buy the gifts of the Holy Spirit for Peter), in its most common form of buying church offices.

Leo steadfastly rejects the council’s bid to raise the status of the patriarch of Constantinople and make his see second only to Rome.

Theodoret, although identified with the Nestorian opposition, is persuaded to renounce Nestorius and is recognized as orthodox.

Eutyches is condemned, deposed, and exiled.

The council’s condemnation of Eutyches’ doctrine of Monophysitism alienates the churches of Egypt, Ethiopia, Syria, Mesopotamia, and Armenia, creating dissension in the Eastern Roman Empire.

Ecclesiastical conflict meanwhile continues.

The Council of Chalcedon, convened in 451 by Pope Leo and the Eastern emperor, is the most notable event of Marcian's reign.

This fourth ecumenical council issues twenty-seven canons governing the Church; it upholds the orthodox Christian doctrine that Christ had two natures, divine and human, and rejects Monophysitism, which maintains that Christ had one divine nature.

As a result of this council, the Oriental Orthodox churches eventually become a separate communion.

More immediately, Jerusalem becomes a Patriarchate and Dioscorus of Alexandria is deposed as patriarch of Antioch.

The Huns, led by Attila in 452, virtually destroy the city of Emona. Its remaining inhabitants flee the city; some of them made it to the coast of Istria.

Eparchius Avitus, born of a distinguished Gallic family, is a son-in-law of the Christian writer Sidonius Apollinaris, whose poetry is an important source for our knowledge of him.

By taking advantage of his great influence with the Visigoths who are settled at Toulouse, Avitus is able in 451 to persuade Theodoric, the first Visigothic leader who can properly be described as a monarch, to join Aetius in repelling the invasion of Gaul by the Huns under Attila.

Galla Placidia, ruler of the Western empire in the name of her weak son Valentinian III, had died at sixty on November 27, 450, clearing the way for Aetius to dominate the imperial government.

In response to the impending Hunnic invasion, Aetius musters in Gaul an army of Burgundians, Celts, Ripuarian and Salian Franks, and Visigoths under the command of the Visigoth king Theodoric I. Eudocia, daughter of emperor Valentinian III, marries Huneric in Ravenna.

The engagement serves to strengthen the alliance between the Western Roman Empire and the Vandal Kingdom.

Attila’s Invasion of Gaul (451 CE)

In the spring of 451 CE, Attila the Hun gathers his vast coalition of vassal tribes, including the Gepids, Heruls, Ostrogoths, Rugians, Scirians, and Thuringians, launching a devastating campaign through Germany. His forces lay waste to settlements, spreading panic and destruction, as terrified populations flee before his advance.

Crossing the Rhine and the Sack of Metz

By the time Attila reaches Belgica, he commands an army of approximately 50,000 men, a force composed of Hunnic cavalry, Germanic auxiliaries, and subject warbands. With his sights set on Gaul, he crosses the Rhine, initiating one of the most destructive invasions of the late Roman world.

On April 7, 451, Metz, a key Gallo-Roman city in Belgica, falls to the Huns. The city is sacked and burned, its inhabitants slaughtered or taken captive. The destruction of Metz sends shockwaves throughout Gaul, as it becomes clear that Rome’s last remaining strongholds are in immediate peril.

The Hun Advance Toward the Heart of Gaul

With Metz in ruins, Attila continues his march deeper into Gaul, laying waste to towns and cities along the way. His goal appears to be the destruction of the Western Roman Empire’s authority in Gaul, possibly with the ultimate aim of capturing Orléans or even Toulouse, the stronghold of the Visigoths.

As Attila advances, Flavius Aetius, Rome’s most experienced general, rushes to assemble a coalition of Roman forces, Visigothic warriors, and other federate allies. Their confrontation at the Battle of the Catalaunian Plains will soon decide the fate of Gaul—and determine whether Attila’s ambition can be stopped.

The Cities Attacked by the Huns: Hagiographic Accounts

The devastation wrought by Attila’s invasion of Gaul in 451 CE can be traced not only through Roman historical records but also through hagiographic vitae—biographies of Christian saints and bishops written to commemorate their deeds. These accounts often blend historical events with miraculous elements, illustrating the religious and cultural impact of the Hunnic onslaught.

The Sack of Rheims and the Martyrdom of Bishop Nicasius

At Rheims, the Huns storm the city, slaughtering many of its inhabitants. According to tradition, Bishop Nicasius, rather than fleeing, chooses to face the invaders in his church, praying at the altar. He is beheaded before the altar, along with his sister Eutropia, his deacon Florens, and other clerics. His martyrdom is later commemorated in local Christian tradition, reinforcing the idea that the city, though ravaged, was spiritually defended.