While Prussian forces and their King Frederick William III fled eastwards to Königsberg in East Prussia to continue resistance, the subsequent Treaty of Tilsit compelled Prussia to cede large portions of its territories and accept French garrisons in its major fortresses and settlements. Prussia became a client state of France, forced to pay large indemnities, and Berlin itself remained occupied until early 1813. A garrison was also established at the nearby Spandau Citadel.