AIGUES-MORTES, a town of south-east France, department of Gard, 25m. S.S.W. of Nimes on a branch line of the P.L.M. railway. Population (1931) 3,629. It occupies an isolated position in the marshy plain at the western extremity of the Rhone delta, 21-m. from the Gulf of Lions. Louis IX. embarked from Aigues-Mortes in 1248 and 127o for the 7th and 8th crusades, and developed the town. The mediaeval fortifi cations which surround it are of great interest. They form a paral lelogram 596yd. long by 149yd. broad and consist of crenellated walls from 25 to 36ft. in height, dominated by towers, of which the Tour de Constance (N.W.), built by Louis IX., was used as a prison for Protestants after the revocation of the Edict of Nantes. The fortifications were completed under Philip III. To further the prosperity of the town a most liberal charter was granted to it, and in addition the trade of the port was artificially fostered by a decree requiring that every vessel navigating within sight of the lights should put in there. This ordinance remained in force till the reign of Louis XIV. The town, although steadily decreasing in population, remains important historically as an outstanding example of mediaeval city planning. Aigues-Mortes is the meet ing-place of several canals connecting with Beaucaire, Cette, the Lesser Rhone and the Mediterranean. Fishing and the manu facture of soda are industries, with trade in coal, fruits and wine. In the surrounding country there are important vineyards, which are preserved from disease by periodical submersion.