Napoleon III ordered the French intervention in Mexico that led to the Battle of Puebla celebrated by Cinco de Mayo.
Napoleon III was the ruler of the Second French Empire from 1852 until 1870. His government joined Britain and Spain in sending troops to Mexico after Benito Juárez suspended foreign-debt payments in 1861. Britain and Spain reached agreements with Mexico and withdrew, but France continued the expedition.
The French campaign had ambitions beyond collecting debts. Napoleon III wanted France to establish a sphere of influence in the Americas and support a monarchy in Mexico. French troops marched toward Mexico City and attacked Puebla on May 5, 1862, but the Mexican army repelled them.
France later sent a larger force, captured Mexico City in 1863, and helped install Maximilian of Austria as emperor. The French withdrew several years later, and Maximilian was captured and executed in 1867. Cinco de Mayo celebrates the earlier Mexican victory rather than the eventual end of the intervention.