The Province of Posen was a province of the Kingdom of Prussia from 1848 to 1920, occupying most of the historical Greater Poland. The province was established following the Poznań Uprising of 1848 as a successor to the Grand Duchy of Posen, which in turn was annexed by Prussia in 1815 from Duchy of Warsaw. It became part of the German Empire in 1871. After World War I, Posen was briefly part of the Free State of Prussia within Weimar Germany, but was dissolved in 1920 when most of its territory was ceded to the Second Polish Republic as a result of the Greater Poland Uprising. The remaining German territory was re-organized into Posen-West Prussia in 1922.

The German Empire, also referred to as Imperial Germany, the Second Reich or simply Germany, was the period of the German Reich from the unification of Germany in 1871 until the November Revolution in 1918, when the German Reich changed its form of government from a monarchy to a republic.