The ancient settlement of Condate, built at the confluent of the Ille and Vilaine rivers in the first century B.C., was probably founded by the Redones, the people of Armorica, and the Romans, the new masters of the whole of Gaul. At the end of the third century, the town known as “Civitas Riedonum” was given its first 1200m-high city wall. In the 15th century, the town’s rapid growth led to the construction of two further city walls to the north-east and south of the Vilaine, increasing the area of the walled city from 9 to 62 hectares. The Tour Duchesne and Portes Mordelaises are the main fortified remains from this period.