Cause:
From 1848 onwards in all the projects for a united Germany there was keen rivalry between Prussia and Austria. Each resisted the domination of the other in any new Empire, and the South German states were inclined to side with Austria against Prussian supremacy. This state of affairs prevented any final scheme from being agreed to. At the same time there were serious differences between Austria and Italy, who was Prussia’s ally. Bismarck made up his mind that Austria must be expelled by force of arms from the German Federation. He was an ardent supporter of the House of Hohenzollern.