The Hun nation was comprised of various un-united tribes that were led by chieftains who were soldiers of fortune with no alliance to a Hun king. Attila knew he would need to pull them together if he was to defeat the Romans, so he began renewing and developing relationships with tribal chieftains. During hunting expeditions throughout the Hunnish territories, he gained the loyalty of these chieftains through emotional appeal, arousing their warrior instincts, and whetting their appetites for easily gained glory and pillage.
After the death of his brother Bleda during a hunt, Attila became king over the tribe in the valley of the Danube and used his leadership skills to unite the other tribes and form his great army. He solicited advice from the warriors as well as the chieftains and persuaded the chieftains that there was more to be gained by working together than by fighting one another or acting as soldiers of fortune for the Romans.
Attila reigned over what was then Europe's largest empire, from 434 AD until his death. His empire stretched from Germany and the Netherlands to the Ural River and from the Danube River to Poland and Estonia. He and his horde were feared throughout Europe as sackers of cities. Attila invaded the Balkans twice and besieged Constantinople in the second invasion. He marched through Gaul (modern day France) as far as Orleans before being defeated at the Battle of Chalons. By AD 451, Attila's horde consisted of 700,000 warriors, and intent on ransacking Rome itself. In 452 AD, he drove the western emperor Valentinian III from his capital at Ravenna.