Main fort of Fort-Louis, former fortress
In 1686, King Louis XIV of France ordered the construction of a fortress in Lower Alsace, directly on the border with the Margraviate of Baden. It was built over a period of ten years from 1687 on an island in the Rhine, which was not yet regulated at the time, according to plans by Sébastien Le Prestre de Vauban and the fortress engineer Jacques Tarade. The medieval palace in Haguenau, around twenty kilometers away, was razed to the ground and the usable stones were used to build the new fortress on the Rhine.
Two outlying forts were built as bridgeheads on the opposite banks of the Rhine, Fort Alsace on the Alsatian side and Fort Marquisat on the Baden bank.
To the south of the main fort, called Fort Carré, the regular street grid of the municipality of Fort-Louis was created on the island, and the king promoted its settlement with privileges. Fort Marquisat had to be abandoned after the Peace of Rijswijk in 1697, and finally after the Peace of Rastatt in 1714.
The main fortress was stormed in 1793 in the First Coalition War and further destroyed in 1815-18.
Since the Rhine was straightened in the 19th century, the fort and the municipality have been located on the left bank of the Rhine.
Remains of the fortress are still there today, with information boards in front of and on the site of the former fortification.