who was the leader who wanted to unify germany (prussia)
William I.
William I, German Emperor
William I or Wilhelm I (; 22 March 1797 – 9 March 1888) of the House of Hohenzollern was King of Prussia from 2 January 1861 and the first German Emperor from 18 January 1871 to his death. William was the first head of state of a united Germany, and was also de facto head of state of Prussia from 1858 to 1861, serving as regent for his brother, Frederick William IV. 
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William I, German Emperor [SEP] Introduction
William I or Wilhelm I (; 22 March 1797 – 9 March 1888) of the House of Hohenzollern was King of Prussia from 2 January 1861 and the first German Emperor from 18 January 1871 to his death. William was the first head of state of a united Germany, and was also de facto head of state of Prussia from 1858 to 1861, serving as regent for his brother, Frederick William IV. Under the leadership of William and his minister president Otto von Bismarck, Prussia achieved the unification of Germany and the establishment of the German Empire. Despite his long support of Bismarck as Minister President, William held strong reservations about some of Bismarck's more reactionary policies, including his anti-Catholicism and tough handling of subordinates.