Following its declaration of war against Spain issued on April 25, 1898, the United States added the Teller Amendment asserting that it would not attempt to exercise hegemony over Cuba. Two days later Commodore George Dewey sailed from Hong Kong with Emilio Aguinaldo on board. Fighting began in the Phillipines Islands at the Battle of Manila Bay on May 1 where Commodore George Dewey reportedly exclaimed, "You may fire when ready, Gridley," and the Spanish fleet under Rear Admiral Patricio Montojo was destroyed. However, Dewey did not have enough manpower to capture Manila so Aguinaldo's guerrillas maintained their operations until 15,000 U.S. troops arrived at the end of July. On the way, the cruiser Charleston stopped at Guam and accepted its surrender from its Spanish governor who was unaware his nation was at war. Although a peace protocol was signed by the two belligerents on August 12, Commodore Dewey and Maj. Gen. Wesley Merritt, leader of the army troops, assaulted Manila the very next day, unaware that peace had been declared.