the foederati (allies) of the Roman Empire in the West and limited to Aquitania and Toulouse, soon began encroaching on neighboring territories. As Roman allies the Visigoths helped defeat Germanic invaders in Spain (notably the Suebi), taking advantage of their position to expand their territory south of the Pyrenees. They tried to conquer the Mediterranean coast of the province of Gallia Narbonensis, but were opposed by Rome. In 439 the Roman general Litorius defeated the Visigoths at Narbonne, driving them back to Toulouse. Although he besieged the city, he was defeated and taken prisoner. Avitus, the praetorian prefect of Gaul with influence on King Theodoric I of the Visigoths, was then sent to Toulouse and concluded a peace. In 451, threatened by an invasion of the Huns in Gaul, he negotiated a treaty between Rome and the Visigoths and they defeated the Huns. In 455 Avitus, magister militum (senior military officer of the Empire) on a diplomatic mission to King Theodoric II of the Visigoths, was proclaimed the new Roman emperor in Toulouse by his Visigothic friends amid news that the Vandals had sacked Rome and Emperor Petronius Maximus had been murdered. Avitus' reign in Rome was brief, and he was defeated by his enemies in 456. This antagonized the Visigoths, who warred with the new Roman leaders, and a weaker Rome gave way. The Narbonne region was conquered by the Visigoths in 462. King Euric (466–484), an enemy of Rome, extended the Visigothic territory in Gaul and Spain. In 475 he dissolved the treaty with Rome, proclaiming independence a year before the fall of the Western Roman Empire. Toulouse was now the capital of an expanding Gothic kingdom; by the end of the fifth century, the kingdom of Toulouse extended from the Loire Valley in the north to the Strait of Gibraltar in the south and from the Rhône in the east to the Atlantic Ocean in the west (the largest territory controlled from Toulouse). Unlike most cities in western Europe, Toulouse remained prosperous during the Migration Period. Although the Visigoths professed Arianism (a non-Trinitarian form of Christianity) and lived apart from their Gallo-Roman subjects, they were generally well accepted for bringing protection and prosperity. Behind its first-century walls, the city encompassed the same area; most western European cities were hastily enclosing small portions of their imperial area. The treasure which the Visigoths seized in Rome in 410 (including