World War I: Start of the Battle of Grand Couronné, a German assault against French positions on high ground near the city of Nancy.

World War I or the First World War, also known as the Great War, was a global conflict between two coalitions: the Allies and the Central Powers. Main areas of conflict included Europe and the Middle East, as well as parts of Africa and the Asia-Pacific. There were important developments in weaponry including tanks, aircraft, artillery, machine guns, and chemical weapons. One of the deadliest conflicts in history, it resulted in an estimated 30 million military casualties, plus another 8 million civilian deaths from war-related causes and genocide. The movement of large numbers of people was a major factor in the deadly Spanish flu pandemic.

The Battle of Grand Couronné from 4 to 13 September 1914, took place in France after the Battle of the Frontiers, at the beginning of the First World War. After the German victories of Sarrebourg and Morhange, pursuit by the German 6th Army and the 7th Army, took four days to regain contact with the French and attack to break through French defences on the Moselle.

Nancy is the prefecture of the northeastern French department of Meurthe-et-Moselle. It was the capital of the Duchy of Lorraine, which was annexed by France under King Louis XV in 1766 and replaced by a province, with Nancy maintained as capital. Following its rise to prominence in the Age of Enlightenment, it was nicknamed the "capital of Eastern France" in the late 19th century. The metropolitan area of Nancy had a population of 508,793 inhabitants as of 2021, making it the 16th-largest functional urban area in France and Lorraine's largest. The population of the city of Nancy proper is 104,387 (2022).