Juan Ponce de Leon founded the first settlement on Puerto Rico, Caparra, in 1508. In 1521 the town was relocated to the site of Old San Juan. San Juan now is the capital of the Commonwealth of Puerto Rico and the island's leading port and manufacturing center. Old San Juan, located on an island in the harbor, is connected by bridges and a causeway to the remainder of the city. The Spanish built two forts during their occupation of the area: El Morro, during the 16th century, and San Cristobal, during the 17th century. The forts successfully guarded San Juan during much of its history. The city passed to the United States in 1898, during the Spanish-American War.