Puerto Rico became a part of the United States as a result of the Spanish- American War. The island was ceded to the United States by Spain in the Treaty of Paris on December 10, 1898. Afterward, Puerto Rico was under U.S. military rule until the Foraker Act of 1900 established a civilian government. Puerto Ricans were granted U.S. citizenship later by the Jones-Shafroth Act which became law on March 2, 1917, officially making Puerto Rico a U.S. territory.