In 422, there was a major Hunnic incursion into Thracia launched from Danube, menacing even Constantinople, which ended with a peace treaty by which Romans had to pay annually 350 pounds of gold. In 432-433, some tribes from Hunnic confederation on the Danube fled to Roman territory and service of Theodosius II. Rugila demanded through his experienced diplomat Esla return of all fugitives, otherwise the peace will be terminated, but soon died and was succeeded by sons of his brother Mundzuk, Bleda and Attila, who became joint rulers of the united Hunnic tribes.