of Prussia and its German allies over the French in the Franco-Prussian War (1870–1871). In 1919, it became French again by the Treaty of Versailles (1919), following the French victory over the Germans in World War I (1914–1918). In 1940, Germany reannexed Alsace-Lorraine following Germany's successful invasion of France. Finally, in 1945, after World War II (1939–1945), Alsace-Lorraine was solidified as French territory, which it remains to this day, more than a thousand years after the Treaty of Verdun. The collapse of the Middle Frankish Kingdom also compounded the disunity of the Italian Peninsula, which persisted into the 19th century. See also Oaths of Strasbourg (842) Treaty of Coulaines (843) Treaty of Prüm (855) Treaty of Meerssen (870) Treaty of Ribemont (880) References External links 843 treaties 9th century in Francia Changes in political power Partition (politics) Treaties involving territorial changes