New towns established by royal decree in the thirteenth century for military purposes are called bastides. In France, bastides were laid out like ancient Roman cities, with a rectangular plan and two principal streets crossing at right angles, dividing the city into four sections with the market square and the church at the center. Walls with towers and fortified gates surrounded the bastide. As duke of Aquitaine, Edward I of England established over fifty bastides as administrative headquarters and commercial centers. These towns were fortified only lightly. The city or bastide of Aigues Mortes was established on the Mediterranean coast by Louis IX as the embarkation spot for his crusade (Figure 22). Rectangular in plan with streets parallel to the walls, and a central open square, five gates on the sea side served the port. The walls were about thirty-five feet high with both wall and corner towers. The Tour de Constance, finished in 1248, a round, moated independent tower, over 100 feet tall with walls nearly 20 feet thick, provided extra security for the governor. The tall turret rising above the wall-walk served as both a watch tower and a lighthouse. Inside the walls, the streets ran straight from gate to gate, crossing at right angles to form rectangular blocks of buildings. A central town square and church served the communityís spiritual and social-commercial needs. Building stopped around 1300. Today the harbor is silted up, and Aigues-Mortes survives as a well-preserved relic of the past.