During his reign, he was one of the most feared enemies of the Western and Eastern Roman Empires. He crossed the Danube twice and plundered the Balkans, but was unable to take Constantinople. His unsuccessful campaign in Persia was followed in 441 by an invasion of the Eastern Roman (Byzantine) Empire, the success of which emboldened Attila to invade the West. He also attempted to conquer Roman Gaul (modern France), crossing the Rhine in 451 and marching as far as Aurelianum (Orléans) before being defeated at the Battle of the Catalaunian Plains.
He subsequently invaded Italy, devastating the northern provinces, but was unable to take Rome. He planned for further campaigns against the Romans, but died in 453. After Attila's death, his close adviser, Ardaric of the Gepids, led a Germanic revolt against Hunnic rule, after which the Hunnic Empire quickly collapsed.
He was a man born into the world to shake the nations, the scourge of all lands, who in some way terrified all mankind by the dreadful rumors noised abroad concerning him. He was haughty in his walk, rolling his eyes hither and thither, so that the power of his proud spirit appeared in the movement of his body. He was indeed a lover of war, yet restrained in action, mighty in counsel, gracious to suppliants and lenient to those who were once received into his protection. Short of stature, with a broad chest and a large head; his eyes were small, his beard thin and sprinkled with grey; and he had a flat nose and tanned skin, showing evidence of his origin.:182–183
Some scholars have suggested that this description is typically East Asian, because it has all the combined features that fit the physical type of people from Eastern Asia, and Attila's ancestors may have come from there.:202 Other historians also believed that the same descriptions were also evident on some Scythian people.