UNNI. – The information provided by Western writers concerning this people is poor and uncertain, nor is much better information gathered from the Chinese sources that knew of them in more ancient times.
Their Mongolian descent is assured by the Chinese sources, which call them Hiung-nu, and by the Western sources, which describe their physical characteristics: small, slender bodies, broad faces with very small eyes. They led a nomadic life in Central Asia and attempted to break into Chinese territories; for defense against them, the Great Wall was built in the 3rd century B.C., joining and unifying earlier fortifications. Around the middle of the 4th century A.D., the U. reached the country inhabited by the Alans north of the Caspian and Volga, and shortly afterward arrived at the Don, which they crossed, driving the Ostrogoths westward.
Then, dragging along with them also the populations of the invaded territories and spreading terror through massacres and destruction, they pushed the Visigoths toward the Danube, who asked to be admitted as federates within the frontiers of the Roman Empire. The U. took advantage in their own way of the latter’s victory at Adrianople in 378, disastrous for the Empire, continuing to infiltrate in groups more or less large, cohesive, and organized into the territories laid waste before their stormy advance, even fighting for the Empire against their own compatriots, without ceasing to plunder and kill. Toward the end of the 4th century, the figure of a leader began to emerge, around whom the greater mass of the U. gathered.
Their principal seat became Pannonia, although from there they continued to spread through their savage raids. Their king Uldin fought against Gaina, a barbarian general in revolt against the emperor Arcadius, and sent his head to Constantinople, receiving as reward an annual tribute of 350 pounds of gold. As a Roman ally, he was present at Fiesole in the battle against Radagasio and his Goths.
The power of the U. continued to grow under Rua, his successor, and especially thereafter under Rua’Attila (v.). The latter gave his State a more solid organization, concentrated all powers in his own hands, and pursued an exceptionally vigorous and active policy with the Eastern Emperor Theodosius II; he succeeded in having the tribute obtained by his predecessor increased to 700 pounds, and later in having it tripled once again; he demanded that all fugitives from his States be handed over to him, even if they were Roman citizens. In the West, all the lands north of the Alps as far as the Rhine were dependent on Attila.
The credit for an almost peaceful coexistence was due in large part to the action of the magister utriusque militiae Aetius, who had for a certain period lived among the U. as a hostage and who, through a shrewd policy, favored now one and now another of the barbarian States, seeking to set them against one another. But Attila’s violent and proud nature could not be content with a peaceful statu quo. Defeated on the Catalaunian Fields (between Chalons and the Argonne) and having returned to his capital, probably in Pannonia, he swept into Italy, where his encounter with the spirited Pope Leo the Great and, no less effectively, the illnesses and hunger of his dissipated army dissuaded him from attempting
the advance on Rome. Having returned to his own territories, Attila died shortly afterward during one of the customary orgies (453), and within a few years the power of the U. disappeared. Later the Avars (v.) were designated by the name of U.