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 that from the Temple in Jerusalem) was reportedly stored in Toulouse at the time. The Visigoths blended Roman and Gothic cultures, preserving Roman law in the 506 Breviary of Alaric (applying to the Visigoths and the local Roman population). The Visigothic kingdom of Toulouse was reportedly more Romanized and its state structure more elaborate than the Frankish kingdom north of the Loire Valley.