Theodoric I Theodoric I ( ; ; ; died in 451 ) , called in Spanish , Portuguese and Italian " Teodorico " , was the Germanic King of the Visigoths from 418 to 451 . An illegitimate son of Alaric , Theodoric is famous for defeating Attila at the Battle of the Catalaunian Plains in 451 , where he was killed . Early career . In 418 he succeeded King Wallia . The Romans had ordered King Wallia to move his people from Iberia to Gaul . As king , Theodoric completed the settlements of the Visigoths in Gallia Aquitania II , Novempopulana and Gallia Narbonensis , and then used the declining power of the Roman Empire to extend his territory to the south . After the death of Emperor Honorius and the usurpation of Joannes in 423 internal power struggles broke out in the Roman Empire . Theodoric used this situation and tried to capture the important road junction Arelate , but the Magister militum Aëtius , who was assisted by the Huns , was able to save the city . The Visigoths concluded a treaty and were given Gallic noblemen as hostages . The later Emperor Avitus visited Theodoric , lived at his court and taught his sons . Expansion to the Mediterranean . Because the Romans had to fight against the Franks , who plundered Cologne and Trier in 435 , and because of other events Theodoric saw the chance to conquer Narbo Martius ( in 436 ) to obtain access to the Mediterranean Sea and the roads to the Pyrenees . But Litorius , with the aid of the Huns , could prevent the capture of the city and drove the Visigoths back to their capital Tolosa . The peace offer of Theodoric was refused , but the king won the decisive battle at Tolosa , and Litorius soon died in Gothic imprisonment from the injuries which he had received in this battle . Avitus went – according to the orders of Aëtius – to Tolosa and offered a peace treaty which Theodoric accepted . Perhaps the Romans recognized at that time the sovereignty of the Visigoth state . Conflict with Vandals . A daughter of Theodoric had been married to Huneric , a son of the Vandal ruler Geiseric ( in 429 ? ) , but Huneric later had ambitions to wed Eudocia , a daughter of the Emperor Valentinian III . He therefore accused the daughter of Theodoric of planning to kill him , and in 444 had her mutilated - her ears and nose cut off - and sent back to her father . This action caused an enmity between the Visigoths and the Vandals . An enemy of Aëtius , the former Magister militum Sebastianus , came in 444 to Tolosa . So there could have emerged strained relations with Aëtius , but Theodoric soon sent his unwelcome guest away who captured Barcelona and was later ( in 450 ) executed at the orders of Geiseric . Theodoric was also an enemy of the Suevi c king Rechila in Iberia , because Visigoth troops assisted the imperial commander Vitus at his campaign against the Suevi in 446 . But the ability of this people to conduct a strong defence and the better relations between Geiseric and the Roman Empire led Theodoric to change his foreign policy . He therefore married in February 449 one of his daughters to the new Suevic king Rechiar , who visited his father - in - law at Tolosa in July 449 . On his return – according to the author Isidore of Seville - Rechiar , with the assistance of Visigoth troops , devastated the area surrounding the city of Caesaraugusta and managed by guile to take Ilerda . Some recent scholars doubt that Theodoric took legislative measures , as it was assumed in earlier times . Alliance against the Huns . When Attila the Hun advanced with his large army to Western Europe and finally invaded Gaul Avitus arranged an alliance between Theodoric and his long - standing enemy Aëtius against the Huns . Theodoric accepted this coalition because he recognized the danger of the Huns to his own realm . With his whole army and his sons , Thorismund and Theodoric , he joined Aëtius . The Visigoth and Roman troops then saved the civitas Aurelianorum and forced Attila to withdraw ( June 451 ) . Battle of Châlons . Then Aëtius and Theodoric followed the Huns and fought against them at the Battle of Châlons near Troyes in about September 451 . Most Visigoths fought at the right wing under the command of Theodoric but a smaller force fought at the left under the command of Thorismund . Theodoric ' s forces contributed decisively to the victory of the Romans , but he himself was killed during the battle . Jordanes records two different accounts of his death : one was that Theodoric was thrown from his horse and trampled to death ; the second was that Theodoric was slain by the spear of the Ostrogoth Andag , who was the father of Jordanes ' s patron Gunthigis . The body of Theodoric was only found at the next day . According to Gothic tradition he was mourned and buried by his warriors on the battlefield . Immediately Thorismund was elected as successor of his father . Other sons of Theodoric were Theodoric II , Frederic , Euric , Retimer and Himnerith .