Marcian (; Latin: Marcianus; Ancient Greek: Μαρκιανός Markianos; c. 392 – 27 January 457) was Roman emperor of the East from 450 to 457. Very little is known of his life before becoming emperor, other than that he was a domesticus (personal assistant) who served under the commanders Ardabur and his son Aspar for fifteen years. After the death of Emperor Theodosius II on 28 July 450, Marcian was made a candidate for the throne by Aspar, who held much influence because of his military power. After a month of negotiations Pulcheria, Theodosius's sister, agreed to marry Marcian. Zeno, a military leader whose influence was similar to Aspar's, may have been involved in these negotiations, as he was given the high-ranking court title of patrician upon Marcian's accession. Marcian was elected and inaugurated on 25 August 450.
Marcian reversed many of the actions of Theodosius II in the Eastern Roman Empire's relationship with the Huns under Attila and in religious matters. Marcian almost immediately revoked all treaties with Attila, ending all subsidy payments to him. In 452, while Attila was raiding Roman Italy, then a part of the Western Roman Empire, Marcian launched expeditions across the Danube into the Great Hungarian Plain, defeating the Huns in their own heartland. This action, accompanied by the famine and plague that broke out in northern Italy, allowed the Western Roman Empire to bribe Attila into retreating from the Italian peninsula.
After Attila's death in 453, Marcian took advantage of the resulting fragmentation of the Hunnic confederation by settling Germanic tribes within Roman lands as foederati ("federates" providing military service in exchange for benefits). Marcian also convened the Council of Chalcedon, which declared that Jesus had two "natures": divine and human. This led to the alienation of the population of the eastern provinces of Syria and Egypt, as many of them were miaphysites, rejecting the new official Christology. Marcian died on 27 January 457, leaving the Eastern Roman Empire with a treasury surplus of seven million solidi coins, an impressive achievement considering the economic ruin inflicted upon the Eastern Roman Empire by the Huns and Theodosius's tribute payments. After his death, Aspar passed over Marcian's son-in-law, Anthemius, and had a military commander, Leo I, elected as emperor.
Marcian was born in c. 392, in either Thrace or Illyria. The ancient historian John Malalas describes him as being tall and having some sort of foot impediment. Little of Marcian's early life is known. His father had served in the military and at a young age Marcian enlisted at Philippopolis in Thrace. By the time of the Roman–Sassanian War of 421–422, Marcian had likely reached the military rank of tribune—the historian Theophanes the Confessor mentions him commanding a military unit. He did not see action in the war, having become ill in Lycia. There he was cared for by Tatianus, who would be made praefectus urbi (prefect of Constantinople) by Marcian, and Tatianus's brother Iulius. Marcian eventually rose to become the domesticus (personal assistant) of Aspar, the magister militum (commander-in-chief) of the Eastern Roman Empire. Despite being half-Alanic and half-Gothic, Aspar held much influence in the empire. In the early 430s, Marcian served under Aspar in Roman Africa, where he was captured by Vandals. Following the imperial propaganda written during Marcian's rule, Evagrius Scholasticus, Procopius and later authors give a likely false account in which Marcian, while in captivity, met the Vandal king Gaiseric, who predicted he would later become emperor. After his capture, Marcian is not mentioned again until the death of the eastern emperor, Theodosius II.
The Eastern Roman Empire was plagued by external threats during the reign of Theodosius II. In 429, the Vandals, led by Gaiseric, began to conquer Roman Africa. Theodosius immediately organized a response, sending Aspar and three other commanders to attempt to repel them in the summer of 431. To the north, the Huns, who had customarily attacked the empire whenever its armies were preoccupied, withdrawing as those forces returned, sent ambassadors to Theodosius in 431, demanding tribute. He agreed to their demand to pay 350 pounds (160 kg) of gold each year. In 434, the Eastern Roman armies were still campaigning against the Vandals in Africa, having faced initial defeats and the withdrawal of many of the Western Roman soldiers. In the face of Eastern Roman weakness, the Huns doubled their demand, asking for 700 pounds (320 kg) of gold per year, which Theodosius agreed to. The threat the Huns posed to his weakly protected empire was enough that Theodosius recalled many of his forces from Africa. With large numbers of the Eastern Roman armies home, and Attila, who had just taken power in the Hunnic Confederation, busy campaigning to the north, Theodosius refused to pay the tribute and continued to refuse to until 439.
On 19 October 439, the Vandals defeated the weakened Eastern Roman armies and captured the major city of Carthage. Both the Western and Eastern Roman Empires began preparing a massive counter-offensive, stripping the Balkan provinces of protection. In the spring of 440, 1,100 ships set sail from Constantinople for Africa; sending away so many of the Eastern Roman forces was a huge gamble on Theodosius's part. He was betting the fortified cities along the Danube could delay the Huns long enough for the invasion force to gain a secure foothold in Africa, allowing troops to be withdrawn back to the northern frontier. This gamble worked until 442 when the bishop of Margus led a raiding party into the Huns' territory and desecrated their royal tombs. In response to this desecration, Attila demanded that the bishop be handed over. To ensure his own safety, the bishop struck a deal with Attila, surrendering the city of Margus to him in exchange for his own life. With control of Margus, Attila had a foothold across the Danube, which he aggressively exploited, capturing and destroying the cities of Viminacium, Singidunum, and Sirmium. Theodosius recalled Aspar to Constantinople and launched a counter-attack. After his force was decisively defeated, Theodosius undertook to pay tribute to the Huns every year, which he did until his death in 450.
After Theodosius II died unexpectedly in a riding accident on 28 July 450, the Eastern Roman Empire faced its first succession crisis in 60 years. Theodosius had no sons, nor had he designated a successor. Some later sources state that he willed the throne to Marcian on his deathbed, but this is thought to be propaganda created by Marcian's supporters after his election. Marcian had served Aspar and his father Ardabur loyally for fifteen years. Aspar conspired to have Marcian elected and was able to negotiate with other powerful figures to have him made the emperor, despite his relative obscurity. There was a one-month interregnum where negotiations for the succession took place, one of which was with Pulcheria, Theodosius II's sister, who agreed to marry Marcian; it is thought that Pulcheria agreed to marry Marcian on the condition that he would abandon Theodosius II's religious policies and convoke a Church council. Their marriage helped to legitimize Marcian's rule, as Pulcheria's family, the Theodosian dynasty, had direct ties to the throne. Despite being married to Marcian, Pulcheria kept the vow of virginity she had made in 413, at age 14, during her three years of marriage to him.
Historian Doug Lee proposes that negotiations were also needed between Aspar and Flavius Zeno, who was in a similar position of military power. Zeno was given the prestigious rank of patrician upon Marcian's ascension in 450, suggesting a deal whereby Zeno was rewarded for supporting Marcian instead of claiming the throne for himself; Zeno would ultimately die within a year of Marcian's accession. Aspar's son, Ardabur, was promoted to command the army of the Prefecture of the East as the new magister militum per Orientem, soon after Marcian's accession.