The annexation of the Philippines was the event in United States history in which the United States took control of the Philippines. The US took these islands from Spain, which had ruled them for centuries, as part of the peace settlement of the Spanish-American War. The war was fought in 1898 and the peace treaty was ratified in 1899.
The Philippines had been a colony of Spain for centuries when war broke out between the US and Spain. The US felt that attacking the Philippines would be a good way to weaken Spain. The Filipinos were, at the time, in the middle of something of a rebellion against Spain. They hoped that the US would help them become independent. Instead, the US decided to take control of the Philippines. This led to a Filipino uprising and a war between some Filipinos and the US. The war lasted until 1902. The Philippines remained as US territory until it was granted independence after World War II.
It was when the US took control over the Philippines, after the Spanish-American war. The war between the US and the Filipinos lasted until 1902. They remained an American territory until after WWII.