The Battle of the Catalaunian plains took place in 451 A.D. between a coalition led by the Romans and the Huns led by Attila. Although the Romans were able to prevent the Huns from establishing vassals in Roman Gaul and as a result were able to claim victory after an inconclusive battle the Huns had successfully looted and pillaged much of Gaul, and crippled the military capacity of the Romans and the Visigoths.
After learning of the Hunnic invasion of Gaul the Roman general Flavius Aetius quickly departed from Italy and led his forces into Gaul. Apparently Aetius did not meet up with the remainder of the coalition forces until he had reached Arles. The Roman coalition included forces from the Visigoths, the Franks, the Burgundians, the Saxons and the Alans. Although it is difficult to determine the exact size of the forces they seem to have been relatively even with approximately 50,000 to 80,000 combatants per side. As soon as the Roman general was able to assemble his coalition he began the pursuit of Attila’s forces. The two forces met somewhere on the Catalaunian plains some time around June 20.
What followed was an inconclusive battle but Attila and his forces departed Gaul, allowing the Romans to claim victory.