Following the German defeat in World War I, the German navy was reorganized as the Reichsmarine according to the Treaty of Versailles. The new navy was permitted to retain eight pre-dreadnought battleships under Article 181 – two of which would be in reserve – for coastal defense.[45] This amounted to three of the Deutschland-class battleships—Hannover, Schleswig-Holstein and Schlesien – as well as the five Braunschweig-class battleships.[46] Hannover was modernized between 1920 and 1921 to prepare her for active service with the fleet. On 10 February 1921, she was recommissioned as the flagship of the Commander of the Naval Forces of the Baltic Sea, KzS und Kommodore (KzS and Commodore) Hugo von Rosenberg.