Alsace-Lorraine, a historic region now part of France. It encompasses the departments of Haut-Rhin and Bas-Rhin (in Alsace) and Moselle (in Lorraine) in northeastern France. Alsace-Lorraine has an area of about 5,600 square miles (14,500 km2) and is bounded by Luxembourg, Germany, and Switzerland. Among its major cities are Strasbourg and Metz. Because of its fertile land, rich mineral deposits, and central location, this region was for centuries a source of bitter conflict between France and Germany.

The Alsace-Lorraine region was part of Roman Gaul in the first century B.C. It was invaded by barbarians beginning in the fourth centurya.d.and eventually was conquered by the Franks. In 843 the treaty of Verdun divided the empire of Charlemagne into three sections, the Alsace-Lorraine region becoming part of the Middle Kingdom of Lothair I. This kingdom (called Lotharingia) later broke up into a number of autonomous states, including Alsace and Lorraine. Both the east Frankish (or German) and the west Frankish (or French) kingdoms repeatedly tried to annex these states.

In the 10th century, Lorraine became a German duchy. Gradually, however, it came under the influence of France. In 1552 the bishoprics of Metz, Toul, and Verdun were seized by the French under Henry II. The rest of the area was governed by its own dukes until 1766, when France gained control of all Lorraine.

Alsace, part of the German duchy of Swabia from the 10th century, was divided into a number of feudal principalities in the 14th century. It remained a part of Germany until the 17th century, although a number of cities, including Strasbourg, were independent. Alsace was occupied by the French during the Thirty Years' War, 1618-48. By the peace of Westphalia, 1648, all Alsace except the bishopric of Strasbourg became French territory. Strasbourg was acquired by France in 1681.

In 1871, following the French defeat in the Franco-Prussian War, Germany annexed most of Alsace and part of Lorraine, forming Alsace-Lorraine. The annexation stirred strong opposition among the people, who resisted attempts to Germanize the region. France regained control in 1919, after World War I. Although the French agreed to respect local customs, they met resistance from some Alsatians who wanted autonomy. During World War II, Germany reoccupied Alsace-Lorraine, 1940–44. It was returned to France after the German defeat.