Battle of Puebla
At the end of October 1861 diplomats from Spain, France, and Britain met in London to form the Tripartite Alliance. The main purpose of this alliance was to launch an allied invasion of Mexico, to take control of Veracruz, its major port. The idea was to force the Mexican government to negotiate terms for repaying its debts and for reparations for harm to foreign citizens in Mexico. In December 1861, Spanish troops landed in Veracruz; British and French followed in early January.