The Franco-Prussian War or Franco-German War, often referred to in France as the War of 1870, was a conflict between the Second French Empire and the North German Confederation led by the Kingdom of Prussia. Lasting from 19 July 1870 to 28 January 1871, the conflict was caused primarily by France's determination to restore its dominant position in continental Europe, which it had lost following Prussia's crushing victory over Austria in 1866. According to some historians, Prussian chancellor Otto von Bismarck deliberately provoked the French into declaring war on Prussia in order to draw four independent southern German states—Baden, Württemberg, Bavaria and Hesse-Darmstadt—to join the North German Confederation; other historians contend that Bismarck exploited the circumstances as they unfolded. None, however, dispute that Bismarck likely recognized the potential for new German alliances, given the situation as a whole.
France mobilised its army on 15 July 1870, leading the North German Confederation to respond with its own mobilisation later that day. On 16 July 1870, the French parliament voted to declare war on Prussia; France invaded German territory on 2 August.