Because of the rising power of the Zollverein, Frederick William IV (1795-1861),[REF] king of Prussia from the death of his father in 1840[REF] until 1861, began to entertain visions of a new political union of German states which would grow out of the Zollverein.
Between 1850 and 1860, the members of the Zollverein adopted a common currency, a common postal system and a common commercial code [REF].