The Puerto Rico quarter is the second in the 2009 District of Columbia and U.S. Territories Quarters Program. Explorer Christopher Columbus arrived at Puerto Rico (“rich port”) in 1493, and it soon became a Spanish colony and important military outpost. Over the years, numerous unsuccessful attempts were made by the French, Dutch and English to conquer the island, but it remained an overseas province of Spain until the Spanish-American War. Under the Treaty of Paris of 1898, it was ceded to the United States, and its residents became American citizens in 1917. On July 3, 1950, Congress passed a law authorizing Puerto Rico to draft its own constitution, and it officially became a United States commonwealth on July 25, 1952.