The walled city of Avaricum, the capital of the Gallic tribe of the Bituriges, was conquered by Julius Caesar in 54 B.C. and became the capital of the Gallo-Roman province of Aquitaine. Christianity was brought by Saint Ursinus of Bourges in about 300 A.D.; He is considered the first Bishop. A "magnificent" church building is mentioned Gregory of Tours in the 6th century. In the 9th century, Raoul de Turenne reconstructed the older building. Between 1013 and 1030 a new and larger cathedral was constructed by the Bishop Gauzelin. Like the earlier churches, it was built against the city wall, and vestiges of it can be found under the present cathedral.