The Alsace region was part of the Holy Roman Empire until France took full control of it in the late 1600s. Though, the Alsatians enjoyed autonomy under the French rule.
France lost the Alsace and Lorraine regions in the Franco-Prussian War to the German Empire in the late 1800s. It was returned to France after World War I under the Treaty of Versailles.
Nazi Germany took Alsace back during World War II in 1940. It went back under French rule after the war in 1944/1945 and remains under France to this day. If you’ve lost count, that’s at least four times, the Alsatians changed nationalities. Its tumultuous history of being caught between two countries can be seen today in its blend of French and German architecture, food, language and wine.