According to Article 181 of the Treaty of Versailles, the treaty that ended World War I, the German Navy was permitted only six light cruisers. Article 190 limited new cruiser designs to and prohibited new construction until the vessel to be replaced was at least twenty years old. Since the six cruisers that German retained had been launched between 1899 and 1902, the oldest ships—, , , , and —could be replaced immediately. Design work on the first new light cruiser, ordered as ""Ersatz Niobe"", began in 1921.