Francis had conspicuously failed to acknowledge Napoleon III as emperor of France following the latter's successful power grab at the start of the decade. Francis of Modena had inadvertently set himself up as eminently dispensable in the eyes of Napoleon. As they traveled round the streets of Plombières, Cavour and Napoleon devised a plan to provoke an appeal for protection from the Modenese citizens to the King of Piedmont-Sardinia, and a demand for annexation of their duchy to Piedmont-Sardinia.