Châlons, battle of (451), also known as the battle of the Catalaunian Plains. Attila the Hun's first and only defeat which halted the previously unchecked advance of the Huns into Europe. Attila, known as the ‘Scourge of God’, was the greatest leader of an extremely warlike people, and after he became king in 443 he led them on long, devastating raids into the declining Roman empire from their base north of the Danube. In 451 the horde rode through Gaul, sacking and burning more than a dozen cities before halting to besiege Orléans.
The Roman military commander Aetius convinced Visigoth King Theodoric of their common danger and their combined army advanced on Orléans. Attila was forced to raise the siege and retreated towards the Seine, looking for a suitable place to give battle, which he believed he had found near Châlons, where the open grasslands of the Champagne plains were suitable for his Hun cavalry. Nonetheless Attila was considerably outnumbered and a small Visigoth force under Theodoric's son Thorismond occupied the tactically important single piece of high ground overlooking the Hun left flank. Aetius and Theodoric had placed their most suspect force, a contingent of Alans, in the centre and they were promptly broken by a Hun cavalry charge. The Huns then wheeled left and fell on Theodoric's Visigoths. Theodoric was killed in the mêlée, but a ferocious counter-attack by Thorismond drove the Huns from the field. Although the battle of Châlons was not a catastrophe, it was of considerable significance as being the first time that Attila had been defeated and suffered serious casualties. Châlons dispelled the myth of invincibility that had worked so potently on both his enemies and allies.
— Chris Mann