Roman–Hunnic Wars was a series of the wars between the Hunas (Hunnics) and the Roman Empire (East and West).

The Huns appeared in Europe after crossing the Volga River from the east, probably shortly before 370 AD. No one knows exactly why they moved, but some think it was because of climate change that dried up grasslands, or because another nomadic group like the Jou-jan pushed them west. They may also have wanted to get closer to the rich Roman lands. Their arrival caused many Goths to flee to the Roman Empire in 376, starting big migrations across Europe. Some sources also say the Huns raided areas near the Caucasus in the 360s and 370s, which made the Romans and Persians defend the mountain passes together.^{[8][9][10][11]}

Uldin was a Hunnic leader who ruled around 400 AD in what is now eastern Romania. He fought and killed the Gothic leader Gainas and sent his head to Emperor Arcadius.^[12] Uldin’s Huns raided Roman lands in Thrace and later helped the Roman general Stilicho defeat the Gothic king Radagaisus in 406. Around 408–409, the Huns attacked the Balkans but were pushed back across the Danube after losing many men. Some Huns joined the Roman army, while others later fought with the Visigoths. Uldin’s power weakened after 409, and by 410 he was replaced by another leader named Charaton. The young Roman general Aetius once lived among the Huns as a hostage, which later helped him understand their ways. Around the same time, the old alliance between the Huns and the Alans broke apart, and many Alans moved west with the Vandals.^{[13][14][1][15]}

When the Hunnic king Rugila died in 434, his nephews Attila and Bleda took control of the united Hun tribes. They made a treaty with the Eastern Roman Empire in 435, where the Romans agreed to pay more gold and return Hunnic refugees. After a few years of peace, the Huns attacked the Sassanid Empire but failed and turned back to Europe.^[16] In 440, they invaded Roman lands again, destroying cities like Margus and Viminacium. As Rome focused on fighting the Vandals in Africa, Attila and Bleda invaded the Balkans in 441, capturing cities such as Belgrade and Sirmium. In 443, they used siege weapons for the first time, taking more cities and defeating Roman armies until they reached Constantinople, which resisted behind strong walls. Emperor Theodosius II had to pay a huge tribute in gold to make peace. Soon after, around 445, Bleda died, and Attila became the sole ruler of the Huns.^[17][18]

In 447, Attila the Hun invaded the Eastern Roman Empire again through Moesia. The Romans, led by the Gothic general Arnegisclus, fought him at the Battle of the Utus but were defeated after a hard fight. With no army left to stop them, the Huns destroyed towns across the Balkans and reached as far as Thermopylae in Greece. Constantinople was saved when the general Zeno brought Isaurian troops to defend it, and the city prefect Constantinus quickly rebuilt and strengthened the city walls that had been damaged by earthquakes.

The barbarian nation of the Huns, which was in Thrace, became so great that more than a hundred cities were captured and Constantinople almost came into danger and most men fled from it. ... And there were so many murders and blood-lettings that the dead could not be numbered. Ay, for they took captive the churches and monasteries and slew the monks and maidens in great numbers.

In 450, Attila the Hun planned to attack the Visigoth kingdom in Gaul, forming an alliance with Emperor Valentinian III. Around the same time, Valentinian’s sister Honoria secretly sent Attila a plea for help and her ring, which he took as a marriage proposal and demanded half the Western Empire as dowry. When the plan was exposed, Honoria was exiled, and Attila claimed he had a right to his “bride’s” land. He then invaded Gaul in 451 with a large army of Huns and allies, destroying cities like Metz and Reims. The Roman general Aëtius gathered Roman, Frankish, and Visigoth forces under King Theodoric I, meeting Attila near Orléans and then at the Battle of the Catalaunian Plains. The Visigoth-Roman alliance won the battle, Theodoric was killed, and Attila was forced to retreat, ending his major campaign in Gaul.^[19][20][21]

In 452, Attila the Hun invaded Italy, claiming he was coming to marry Honoria, the sister of Emperor Valentinian III. His army destroyed cities across northern Italy, including Aquileia, which was left in ruins, and forced many people to flee to the islands that later became Venice. The Roman general Aëtius could not stop him but slowed his march until disease, hunger, and exhaustion weakened the Huns. At the River Po, Attila met a Roman delegation led by Pope Leo I, who persuaded him to leave Italy and make peace.^[22] Famine and lack of supplies also made further invasion impossible, and attacks by Eastern Roman forces on Hunnic lands pushed Attila to retreat back across the Danube.^[23]

The Huns, who had been plundering Italy and who had also stormed a number of cities, were victims of divine punishment, being visited with heaven-sent disasters: famine and some kind of disease. In addition, they were slaughtered by auxiliaries sent by the Emperor Marcian and led by Aetius, and at the same time, they were crushed in their [home] settlements ... Thus crushed, they made peace with the Romans.^[24]

After Attila’s death, his sons fought to keep the Hunnic Empire together. His eldest son, Ellac, was killed in 454 at the Battle of Nedao, where the Huns were defeated by the Goths. Another son, Dengizich, and his brother Ernak later tried to make peace and trade with the Eastern Roman Empire, but their requests were refused. Dengizich then crossed the Danube around 467 and attacked Roman lands in Thrace, but was met by Roman generals and their Gothic allies. After years of fighting, the Huns were defeated again, and many of their allies turned against them. In 469, Dengizich tried to invade Pannonia but was crushed by the Goths at the Battle of Bassianae. His head was sent to Constantinople and displayed on a pole, marking the final collapse of Hunnic power in Europe.^[1][25]

Historian Kim argues that after Attila’s death, the wars that followed were not just revolts by other tribes but a civil war within the Hunnic Empire, with Ardaric leading the western Huns against Ellac and the eastern Huns. He believes Ardaric and other Gepid leaders were actually Huns, not Germanic, and that their rule was similar to the Huns’. Ardaric’s descendants, like Mundo, were called both Huns and Gepids. Kim also claims that other leaders from Attila’s empire, such as Edeco and his sons Hunoulph and Odoacer, were of Hunnic origin, even though they ruled mainly Germanic troops. The Goths under Valamir and his family also broke away but may have stayed loyal to the Huns for years. Battles between Goths, Sciri, and others marked the final end of Hunnic power in the West. Kim concludes that many major European leaders after Attila were really Huns or came from his empire, though some historians, like Warwick Ball, think Kim’s ideas exaggerate Hunnic influence.^[11][14]

Attila the Hun turned west after receiving a message from Honoria, sister of the Roman Emperor, asking for help because she was being forced to marry. Attila said she was his wife and demanded half of the Western Roman Empire as her dowry. When this was refused, he invaded Gaul in 451 but was stopped at the Battle of the Catalaunian Plains by Roman general Aetius and his allies. The next year, he invaded Italy but stopped his march on Rome because of disease, hunger, attacks on his lands, and a peace plea from Pope Leo I. Attila died suddenly in 453, and his empire quickly fell apart as his followers fought each other. After his death, the Romans on the Upper Danube were left weak and unprotected, suffering raids, killings, and looting from nearby barbarian tribes.^[26]

• Gupta–Hunnic Wars
• Huna people

• Kim, Hyun Jin (2016). The Huns. Routledge. ISBN 978-1-138-84175-8.
• Maenchen-Helfen, Otto (1973). The World of the Huns: Studies in Their History and Culture. Berkeley: University of California Press. ISBN 0-520-01596-7.