The Austro-Prussian War of 1866 was triggered by the desire of German conservative leaders to unify, albeit on different terms than their liberal counterparts. Ernest urged Prussian leaders against the impending war, and was an active advocate of the Austrian cause. Though Ernest normally followed more liberal politics than many of his counterparts, he began switching his views to align more closely with Bismarck by the mid-1860s. Despite this change in his private political views, he still had strong publicly known ties to Austria, where his cousin Alexander, Count Mensdorff, was Foreign Minister, and no one foresaw that Ernest would immediately side with the better-equipped Prussians upon breakout of the war. His reasoning is usually understood as acting in the best interests of his duchies, and by extension, of himself. Some influence came from Bismarck, who explained his policy and tactics in a letter to Ernest. Regardless, it was seen as a betrayal of former friends; Queen Victoria commented that Ernest "might have agreed to neutrality—for that might be necessary, but to change colours I cannot think right".