In 1866, Otto von Bismarck, Minister President of Prussia, offered Victor Emmanuel II an alliance with the Kingdom of Prussia in the Austro-Prussian War. In exchange, Prussia would allow Italy to annex Austrian-controlled Veneto. King Emmanuel agreed to the alliance and the Third Italian War of Independence began. Italy fared poorly in the war with a badly-organized military against Austria, but Prussia's victory allowed Italy to annex Veneto. At this point, one major obstacle to Italian unity remained: Rome.