The city was conquered by France under King Louis XIV in 1673 and officially ceded by the 1679 Treaties of Nijmegen. With the rest of Alsace, Colmar was annexed by the newly formed German Empire in 1871 as a result of the Franco-Prussian War and incorporated into the Alsace-Lorraine province. It returned to France after World War I according to the 1919 Treaty of Versailles, was annexed by Nazi Germany in 1940, and then reverted to French control after the battle of the "Colmar Pocket" in 1945. Colmar has been continuously governed by conservative parties since 1947, the Popular Republican Movement (1947–1977), the Union for French Democracy (1977–1995) and the Union for a Popular Movement (since 1995), and has had only three mayors during that time.Colmar was founded in the 9th century. This was the location where the Carolingian Emperor Charles the Fat held a diet in 884. Colmar was granted the status of a free imperial city by Emperor Frederick II in 1226. In 1354 it joined the Décapole city league. The city adopted the Protestant Reformation in 1575, long after the northern neighbours of Strasbourg and Sélestat. During the Thirty Years' War, it was taken by the Swedisharmy in 1632, who held it for two years. In 1548 Josel of Rosheim urged the Reichskammergericht court to repeal the Colmar market ban for Jewish merchants.
The Colmar Treasure, a hoard of precious objects hidden by Jews during the Black Death, was discovered here in 1863.
