 Frederick William IV was followed by his brother William I on 2 January 1861.He changed the arms on 11 January 1864 by combining the escutcheons of Nuremberg and Hohenzollern.After the Second Schleswig War of 1864 and the Austro-Prussian War of 1866, Prussia annexed Schleswig, Holstein, Hanover, Hesse-Kassel (or Hesse-Cassel), and Nassau.