Ruga, a king of the Huns, negotiated a treaty with the Eastern Roman Empire in 433. In exchange for allowing his soldiers to fight on behalf of that empire, Ruga and his people were given land in Pannonia.
Then a province of Rome, Pannonia today is known as the Carpathian Basin. It roughly corresponds to western Hungary, parts of eastern Austria, plus portions of Serbia, Croatia and Slovenia.
After 395, when the "Barbarian Invasions" threatened Roman territories, Pannonia ceased to exist as a province of Rome.
Image online, courtesy Wikimedia Commons.