Tour de Constance, Fortified tower in Aigues-Mortes, France.

Tour de Constance is a round fortified tower built from 1242 to 1254 under Louis IX, standing outside the town walls of Aigues-Mortes and linked to them by a bridge. Its walls are 6 m thick at the base, and it measures 22 m in diameter. The two main halls, the guardroom and the knights' hall, rise 12 m and are covered by domes divided into 12 sections resting on slender Gothic columns. A watchtower about 11 m high, once a lighthouse, tops the terrace.

Louis IX built the tower from 1242 to 1254 on the site of the Tour Matafère, attributed to Charlemagne around 790, to give his kingdom a Mediterranean port. In November 1307 Philippe le Bel had forty-five Templars imprisoned and questioned here. After the revocation of the Edict of Nantes it held Protestant women, among them Marie Durand, detained at 19 and freed 38 years later.

The tower's name comes from the constancy of Huguenot women imprisoned here after the 1685 revocation of the Edict of Nantes. The best known, Marie Durand, was held from age 19 for 38 years and is said to have carved the word REGISTER (resist) on the well rim in the knights' hall, still visible today.

The tower stands outside the town wall and is reached by a three-arch bridge. Inside, a narrow wall-walk between the guard room and the knights' hall lets you look down into the lower room. The terrace is open to the sky and the watchtower rises from it.

The word REGISTER, said to have been scratched by Marie Durand on the well rim in the knights' hall, remains legible today. Durand was imprisoned at 19 and freed 38 years later; Anne Salièges, held from infancy, left after 71 years in 1772.