The chief of Pago Pago signed a treaty with the U.S. in 1872, giving the American government considerable influence on the island. It was acquired by the United States through a treaty in 1877. One year after the naval base was built at Pearl Harbor in 1887, the U.S. government established a naval station in Pago Pago. It was primarily used as a fueling station for both naval- and commercial ships.