When the United States declared war on Spain on April 25, 1898, acting Secretary of the Navy Theodore Roosevelt ordered Commodore George Dewey, commander of the Asiatic Squadron, to sail to the Philippines and destroy the Spanish fleet anchored in Manila Bay. Dewey's flagship, the USS Olympia, was more heavily armed than earlier US cruisers and could also move much faster at 21.4 knots (over 24 miles an hour). On May Day at dawn, the Olympia steamed into the waters of Manila Bay, launching the first shell at the Spanish ships. When the entire American fleet opened fire, the Spanish were quickly defeated. The Spanish navy, which had seen its apogee in the support of a global empire in the sixteenth century, suffered an inglorious defeat, as Spain's antiquated fleet, including ships with wooden hulls, was sunk by the guns of Dewey's flagship, the Olympia, and other United States warships. More than 380 Spanish sailors died, but there was only one American fatality.
The Manila campaign was a sequel to the first naval engagement of the war. On 1 May 1898 a small American squadron under Comdr. George Dewey completely destroyed a Spanish naval force in Manila Bay.