April 1, 1901, Emilio Aguinaldo volunteered to swear his allegiance to the United States
On April 1, 1901, Emilio Aguinaldo volunteered to swear his allegiance to the United States, formally ending the First Republic and recognizing the sovereignty of the US over the Philippines. He signed an oath of allegiance to the United States, nine days after his capture, in return for his release from incarceration. Aguinaldo was captured by the Americans in his secret headquarters in Palanan, Isabela on March 23, 1901.
After his capture, Aguinaldo was held at the Malacañang palace as a POW but was treated more as guest than a prisoner from March 28th until April 20th of 1901.
It was Chief Justice Arellano, formerly attorney general in Aguinaldo’s cabinet, who persuaded him to swear allegiance to the United States, and on April 19, 1901, issued a proclamation acknowledging and accepting the sovereignty of the United States throughout the Philippine Archipelago.
Aguinaldo is considered to be the country’s first and the youngest President from March 22, 1897 to April 1,1901, though his government failed to obtain any foreign recognition.
St. Louis Post-Dispatch, April 3, 1901, p1. (quoted in Wikipedia)