The Philippine–American War began when an American soldier, under orders to keep insurgents away from his unit's encampment, fired on a Filipino soldier in Manila.

The Philippine–American War, known alternatively as the Philippine Insurrection, Filipino–American War, or Tagalog Insurgency, emerged following the conclusion of the Spanish–American War in December 1898 when the United States annexed the Philippine Islands under the Treaty of Paris. Philippine nationalists constituted the First Philippine Republic in January 1899, seven months after signing the Philippine Declaration of Independence. The United States did not recognize either event as legitimate, and tensions escalated until fighting commenced on February 4, 1899, in the Battle of Manila.

The Battle of Manila, the first and largest battle of the Philippine–American War, was fought on February 4–5, 1899, between 19,000 American soldiers and 15,000 Filipino armed militiamen. Armed conflict broke out when American troops, under orders to turn away insurgents from their encampment, fired upon an encroaching group of Filipinos. Philippine President Emilio Aguinaldo attempted to broker a ceasefire, but American General Elwell Stephen Otis rejected it, and fighting escalated the next day. It ended in an American victory, although minor skirmishes continued for several days afterward.