After the Treaties of Tilsit in 1807, Prussia lost about half of its territory, including the land gained from the Second and Third Partitions of Poland (which now fell to the Duchy of Warsaw) and all land west of the Elbe River.
Despois do Tratado de Tilsit en 1807, Prusia perdeu case a metade do seu territorio, incluídas as terras gañadas nas Segunda e Terceira Particións de Polonia (que agora se resumía ao Ducado de Varsovia) nas terras ao oeste do Río Elba.