The Austro-Prussian War of 1866 was a decisive conflict between the Austrian Empire and the Kingdom of Prussia for dominance over the German states.

The immediate pretext was a dispute over the administration of the territories of Schleswig-Holstein.

Bismarck skillfully prepared for the war diplomatically, securing the neutrality of Russia and France and an alliance with Italy.

The Prussian army had a significant advantage due to its superior organization and technology.

The Prussian use of the needle gun, a breech-loading rifle, allowed for a much faster rate of fire than the Austrian muzzle-loading rifles.

Prussia's extensive railway network enabled the rapid mobilization and deployment of its troops.

The decisive battle of the war was the Battle of Königgrätz (or Sadowa), which resulted in a crushing Prussian victory.

The war was surprisingly short, lasting only about seven weeks.

Bismarck imposed a lenient peace on Austria, not taking any of its territory, to ensure it would not be a future enemy.

The war's outcome was the dissolution of the old German Confederation and the permanent exclusion of Austria from German affairs.