Battle of the Catalaunian Plains, (ad 451), battle fought between the Huns under Attila and a mixed Roman and Visigoth force under Aetius and Theodoric I; it checked the Hunnic advance in Europe. The exact location of the encounter is in dispute, with opinion divided between Châlons and Troyes, both on the Catalaunian Plains (Latin Campi Catalauni) in Champagne, eastern France.
The battle, long-remembered for its ferocity, resulted in Attila’s defeat, though the casualty figures in traditional accounts are probably exaggerated. The Huns’ defeat prevented the widespread destruction and spoliation of Gaul, but it is unlikely that Attila’s horde could have made any deep impression upon the Latin and urban character of the country.