Saarlouis is a city in the Saarland, Germany, capital of the district of Saarlouis. In 2006, the town had a population of 38,327. Saarlouis, as the name implies, is located on the River Saar. It was built as a fortress in 1680 and named after Louis XIV of France.HistoryWith the Treaties of Peace of Nijmegen in 1678/79, the Lorraine fell to France. In 1680, Louis XIV of France gave order to build a fortification (to defend the new French Eastern frontier) on the banks of the river Saar which was called Sarre-Louis. France's famous military engineer, Sébastien Le Prestre de Vauban, constructed the city, the plans were made by Thomas de Choisy, the city's first Gouvenour. In 1683, Louis XIV visited the fortress and granted arms. The coat of arms shows the rising sun and three Fleur-de-lis. The heraldic motto is Dissipat Atque Fovet: He (the Sun) dispels (the clouds) and heats (the earth).In 1697, with the Treaty of Ryswick, most parts of Lorraine gained independence again, but Saarlouis and the surrounding areas remained a French exclave. During the French Revolution, the town was renamed Sarre-Libre, but it returned to its original name in 1810. With the Treaty of Paris in 1815, Saarlouis (and the whole region later known as the Saargebiet) became Prussian.