When the Spanish found gold on Puerto Rico, they established farms for cattle, grain, fruits, and vegetables to supply mining camps. These farms later grew into large and small plantations for cash crops of sugarcane, tobacco, and coffee.

The Spanish enslaved the Taínos to work the mines and farms. But the native people died of abuse, suicide, and contagious diseases introduced by the Spanish. By 1520, the Taíno presence had almost vanished, and Spain turned to West and Central Africa for labor-enslaving hundreds of thousands of men, women, and children until slavery ended in 1873.

During the 1700s, Puerto Ricans began to develop their distinctive traditions and practices. The island received refugees from the Napoleonic Wars and other European immigrants after 1815. The contemporary culture of Puerto Rico emerged from the blending of European, African, and Native American traditions.

Spanish explorer Juan Ponce de León (1460-1521) became the first Spanish governor of this Crown Colony in 1509. His highly centralized government controlled the colony's economic and social life.

Roman Catholic priests who arrived with the explorers and soldiers came to convert native peoples. But the goals of the Crown and the Church sometimes clashed, as when priests criticized the way landowners treated enslaved Catholic converts. Slavery was brutal throughout the Americas. Farming cash crops for export required thousands of people to work the fields. The Spanish enslaved African peoples to do this work. African peoples and their mixed descendants contributed to the development of Puerto Rico's creolized society. By 1800, the population was 15 percent slaves, 40 percent free people of color, and 45 percent other free people. Slavery ended in 1873, but the African presence is woven into Puerto Rico's language, music, cuisine, art, religious practices, and everyday ways of living.

By the 1890s, Puerto Rican political activists, writers, and other intellectuals began to organize political parties. Some favored a break with Spain. Others favored political autonomy while remaining part of Spain. Still others wanted no change at all in the relationship with the Crown.

In 1897, four men were sent as deputies to the Cortes, the empire's legislative body in Cádiz, Spain. They secured a Charter of Autonomy that gave Puerto Rico increased self-governance and declared universal male suffrage.

On February 15, 1898, the U.S.S. Maine sank in Cuba's Havana Harbor. The United States declared war against Spain. U.S. forces defeated Spanish defenses in Cuba, Puerto Rico, the Philippine Islands, and Guam in the Pacific. Victory in this short war marked the United States' emergence as an imperial nation. Spain ceded "Porto Rico" to the United States through the Treaty of Paris on December 10, 1898.

The USA ruled Puerto Rico as a colonial protectorate for the next five decades, despite continued calls for autonomy. Puerto Ricans were granted US citizenship in 1917, just in time for them to be eligible for military service in WWI. Reform and investment improved the economy for large landholders (particularly US sugar interests), but the 1930s depression hit the island hard and the independence movement turned to violence.

During World War II, the US military appropriated extensive agricultural lands that have never been returned, including the loudly disputed island of Vieques. Puerto Rico won the right to elect its own governor in 1948, shortly after President Truman implemented 'Operation Bootstrap,' aimed at kickstarting the island's economy, largely by forcing the sale of many publicly owned enterprises and giving tax breaks to resident US companies.

Puerto Ricans voted three to one in a 1951 referendum to become a commonwealth of the US rather than remain a colony. Nationalists seeking full independence took the fight to the US mainland where they attempted to assassinate President Truman and opened fire on US congressmen from the visitors' gallery in the House of Representatives. Political support for full independence waned and calls for US statehood increased, though neither independence nor statehood has ever won a majority vote in any of numerous referenda on status.

The Puerto Rican economy continued to post impressive gains in GNP, around one million Puerto Ricans went to work in New York City and elsewhere in the US during the 1950s and '60s. Return migration to Puerto Rico increased during the 1970s and '80s; US citizenship has helped facilitate a type of circular migration that has led some intellectual types to label Puerto Rico the 'commuter nation.'