When president Anastasio Bustamante made no payment, the King of France ordered a fleet under Rear Admiral Charles Baudin to declare and carry out a blockade of all Mexican ports on the Gulf of Mexico from Yucatán to the Rio Grande, to bombard the Mexican fortress of San Juan de Ulúa, and to seize the city of Veracruz, which was the most important port on the Gulf coast. French forces captured Veracruz by December 1838 and Mexico declared war on France.