Political map of Europe & the Mediterranean 28 January 1871 (Unification of Germany and Fall of Paris): On 18 January 1871, King William of Prussia (William I, German Emperor) was declared Emperor of Germany by the leaders of the German states (Unification of Germany) at Versailles Palace in France. Ten days later, Paris capitulated (Siege of Paris (1870%E2%80%931871)) and the French agreed to peace.