The province was a battleground in 1914-15, when, following the outbreak of the [[First World War]] Russian armies invaded the province but were decisively defeated at the [[Battle of Tannenberg]] in 1914 and the Battle of the Masurian Lakes. Following Germany's defeat in 1918, the [[Treaty of Versailles]] divided Germany and the state of Poland re-created, which included the [[Polish Corridor]] to the Baltic Sea and the port city of [[Danzig]] (later Gdansk) declared a "Free City", neither part of Germany or Poland. East Prussia remained part of [[Germany]] (with the exception of the port of [[Memel]], seized by newly-independent [[Lithuania]]). In 1939 [[Nazi Germany]] forced Lithuania to relinquish Memel. | The province was a battleground in 1914-15, when, following the outbreak of the [[First World War]] Russian armies invaded the province but were decisively defeated at the [[Battle of Tannenberg]] in 1914 and the Battle of the Masurian Lakes. Following Germany's defeat in 1918, the [[Treaty of Versailles]] divided Germany and the state of Poland re-created, which included the [[Polish Corridor]] to the Baltic Sea and the port city of [[Danzig]] (later Gdansk) declared a "Free City", neither part of Germany or Poland. East Prussia remained part of [[Germany]] (with the exception of the port of [[Memel]], seized by newly-independent [[Lithuania]]). In 1939 [[Nazi Germany]] forced Lithuania to relinquish Memel. |