Germany By pgannon20 Period: 1840 to 1861 King Frederick William IV of Prussia 1848 Frankfurt Assembly fails to unify Germany Period: 1861 to 1888 King William (Wilhelm) I of Prussia 1864 Prussia and Austria capture Schleswig and Holstein from Denmark 1866 Prussia defeats Austria in the Seven Weeks War Period: 1871 to 1918 German 2nd Reich Period: 1871 to 1890 Bismarck’s service as prime minister/chancellor Period: 1888 to 1918 Emperor William (Wilhelm) II of Germany