The major cause for the Third Italian War of Independence was:
- The simultaneous attack of Austria by Prussia and Italy in 1866.
During the Third Italian War of Independence, both Prussia and Italy joined forces to attack Austria. Prussia's main goal was to weaken Austria's power and influence in the German Confederation, while Italy sought to gain control of Venetia, which was under Austrian rule. This joint military action against Austria was a significant factor that led to the outbreak of the war.
The desire to create a vast Italian empire in central Europe was not a major cause for the Third Italian War of Independence. Italy's main focus during this conflict was on gaining independence and unifying Italian territories under the Kingdom of Italy.
The border disputes with France and later with Prussia were not the primary cause of the Third Italian War of Independence. While border disputes did exist between various European powers during this time, the conflict between Austria, Prussia, and Italy was more directly related to their specific territorial and political goals.
The belief that the Papal States should remain independent of Italy was a factor in Italian unification efforts but was not a major cause of the Third Italian War of Independence. The war was more about challenging Austrian control over Italian territories and furthering the cause of Italian unification rather than specifically focusing on the Papal States' independence.
