Multiple choice The dispute that sparked the Franco-Prussian War concerned a Hohenzollern rising to the Spanish throne. Bismarck's decision to invade Luxembourg. The French invasion of Alsace and Lorraine. Napoleon III's annexation of Schleswig-Holstein. Reveal answer Fill a bubble to check yourself A Correct answer Explanation The immediate trigger for the war was the Ems Dispatch, which concerned the candidacy of a Hohenzollern prince for the Spanish throne, an event France viewed as a threat to its security.