The castle at Angers has a less imposing site but a remarkable surviving towered wall (Figure 17). Angers was originally a Celtic settlement on the border with Brittany and then a Roman town. The counts of Anjou made Angers their capital in the tenth century. In the thirteenth century Anjou became part of France. Blanche of Castile, the mother of King Louis IX and regent until he came of age in 1234, built much of the huge castle we see today (122838). The castle stood on a cliff on the left bank overlooking an island and the river Maine (a tributary of the Loire) at the northwest corner of the old town. A suburb arose across the river on the right bank, and a wall reinforced with rounded towers broken by three fortified gates surrounded the entire city. Outside the walls a moat added to the defenses and also separated the castle from the town. The castle had seventeen towers and two towered gatehouses. In spired by crusader castles and the walls of Constantinople, the masons raised walls and towers that display dark and light banded layers, a late Roman and Byzantine technique. Only one tower, the Mill Tower on the north corner, still has its original height. The moat now combines a deer park with extensive formal gardens. In constant use, the castle was refurbished in 1384 by Duke Louis II of Anjou, and in 1450 and 1465 by Duke Rene of Anjou. By the end of the fifteenth century the kings constable remodeled the castle into a fortress designed for artillery. The tall towers, which had lost their effectiveness (towers made excellent targets for gunners), were cut down to the height of the curtain walls (about 5868 feet) and turned into platforms to support cannon. The walls facing the town were thickened to form a wide platform, and casemates (storage rooms within the walls) were added to all the walls and towers. A barbican and an additional rampart and tower suitable for artillery were also added. This new work was finished by 1592. Later used as an army headquarters and a prison, the castle today is a designated historic monument containing gardens, a chapel, and a museum for the fourteenth-century tapestry known as the Angers Apocalypse.