In early 451, Attila crossed the Rhine River with a large army of Huns, Ostrogoths, Gepids and other allies and ravaged Gaul, sacking Rheims, Mainz, Strasbourg, Cologne, Worms and Trier. Even Paris was threatened behind its thick walls before Attila turned his attention to Orleans, the capital city of the Iranian Alans in central Gaul. But Orleans was strictly defended by Sangiban (Sangi=Stony & Ban=Keeper), the Alanian king. therefore Attila was forced to abandon the seige of Orleans and retired with his army to the open country near Chalons and Troyes known as the Catalaunian Plains.
The Battle of Chalons (451 AD) [or Battle of Catalaunian Plains]
Attila formed his army in three divisions, with his Hunnic cavalry in the center, the Gepids and other German allies on the right, and his Ostrogothic allies on the left. Sangiban also formed his army into three main divisions, with his Alani cavarly in the center, Visigothic cavalry and infantry on the right, and Romans, Gallo-Romans, Frank and allied Germans on the left.
After fierce fighting, in which the Visigothic king was killed, Attila withdrew and shortly afterward retired from Gaul. This was his first and only defeat.