The mighty Spanish Empire that at its height held much of South American and Mexico, that was the first to colonize North America, was a shadow of its former self by 1825. Only the Philippines archipelago remained, several minor islands in the Pacific, and Cuba — which wanted out. Cuban mambisos waged a guerrilla campaign to drive out the Spanish, and gained no small amount of sympathy from the United States. President Grover Cleveland was still reluctant to commit the U.S. to the fight, but did agree to a show of force by sending the battleship Maine to Havana. When the Maine blew up in the Cuban harbor, under mysterious circumstances, Cleveland had no choice but to declare war.

On this day, April 21 in 1898 President McKinley orders a blockade of Cuba, in preparation for war with the Spanish. Official declaration came four days later, and the U.S. loaded ships with troops bound for Cuba and the Philippines.

Although Cuba was the closer island, the first battle of the war came near Manila Harbor in the Philippines. Commodore George Dewey had a fleet assembled at Hong Kong and sailed as soon as word came down that war was declared. Dewey, on board the Olympia began the American assault on the Spanish flotilla with the famous phrase “You may fire when ready, Gridley.”