Christopher Columbus was on his second voyage in his quest to “discover” the New World when he arrived in Puerto Rico in 1493. There is debate as to where exactly Columbus, called Colón by the Spanish, first disembarked on the island. That momentous occasion is claimed by Aguada, on the northwest coast of the Atlantic, and Guánica, on the southwest coast of the Caribbean. Either way, he didn’t stick around long enough to do much more than christen the island San Juan Bautista, after John the Baptist.

It wasn’t until 1508 that Juan Ponce de León, who had been on the voyage with Columbus, returned to the island to establish a settlement. The Taíno provided no resistance to his arrival. In fact, Taíno cacique Agueybana allowed Ponce de León to pick any spot he wanted for a settlement so long as the Spanish would help defend the Taíno against the Caribs. His choice of Caparra, a marshy mosquito-ridden spot just west of what is now San Juan, was a poor one.

Around 1521 the settlement was relocated to what is now Old San Juan, and in 1523 Casa Blanca was built to house Ponce de León and his family, although by that time the explorer had left for Florida, where he met his demise. Originally the new settlement was called Puerto Rico for its “rich port.” It’s not clear why—possibly a cartographer’s mistake—but soon after it was founded, the name of the settlement was switched with the name of the island.

San Juan quickly became a vital port to the Spanish Empire. An important stopover for ships transporting goods from the New World to Europe, it soon became a target for foreign powers. To protect its interests, Spain began a centuries-long effort to construct a formidable series of fortresses to defend the harbor and the city.

Construction of the island’s first Spanish fort, La Fortaleza, began in 1533. The small structure, which to this day serves as home to the island’s governor, was built to store gold and protect it from Carib attacks. The port quickly grew in importance, and Spain’s enemies—England, Holland, and France—began to threaten it with attacks. More elaborate defense systems were needed. To protect the city’s all-important harbor, construction of El Morro castle began in 1539, forming the nucleus of the city’s fortifications. Through the years it was expanded to four levels and five acres before completion in 1787.

To protect the city from attack by land, San Cristóbal castle was begun in 1634. By the time it was completed in 1783, it was the city’s largest fort, spanning 27 acres. That same year began the 200-year construction of La Muralla, the massive stone wall that once encircled the city and much of which still stands. It contained five gates which were closed at night and guarded at all times.

The English were the first to significantly damage the city. In 1595, Sir Francis Drake led 26 vessels in an attack that partially burned the city but was successfully repelled. The next English attack proved more fruitful. Led by George Clifford, the earl of Cumberland, troops landed in Santurce in 1598 and occupied the city for several months before illness and exhaustion forced them to abandon their stronghold.

The most devastating attack to date came when 17 Dutch ships led by Boudoin Hendricks attacked in 1625. And in 1797 the British, led by Sir Ralph Abercrombie, attacked again.

Meanwhile, other settlements were being established throughout the island. The area now known as Aguada was established as Villa de Sotomayor in 1508, but it was destroyed by Indians in 1511. In 1516, Franciscan friars built a monastery nearby, which was destroyed by Indians 12 years later. A new monastery was built in 1590, followed by a chapel in 1639. Also an important stopover for ships on their way to Spain from South America, it suffered attacks by the English, French, and Dutch. San Germán was founded in 1573 and was attacked by pirates, the English, and the Dutch. Arecibo followed in 1606.

Attack by foreign powers waned in the 1800s, and the island’s sugarcane and coffee plantations flourished because of the slave labor that was brought in from Africa. But by the 1860s, a new challenge to Spanish rule arose in the form of an independence rebellion that was brewing among the island’s rural class.

On September 23, 1868, about 500 Puerto Ricans organized a revolt, proclaiming the mountain town of Lares free of Spanish rule. Local stores and offices owned by Spanish merchants were looted, slaves were declared free, and city hall was stormed. The revolt was quickly squelched the next day, when rebel forces attempted to take over a neighboring town. The revolutionaries, including leaders Manuel Rojas and Juan Rius Rivera, were taken prisoner, found guilty of treason and sedition, and sentenced to death. But to ease the political tension that was brewing on the island at that time, the revolutionaries were eventually released. Although the revolt, referred to as Grito de Lares, was unsuccessful, it did result in Spain’s giving the island more autonomy.

Colonial reforms were made, national political parties were established, and slavery was abolished. But at the same time, restrictions were imposed on human rights, such as freedom of the press and the right to gather. Meanwhile, the Spanish Empire was beginning to crumble. It eventually lost all its Caribbean colonies except Cuba and Puerto Rico, and increased tariffs and taxes were imposed on imports and exports to help fund Spain’s efforts to regain control of the nearby Dominican Republic. Living conditions in Puerto Rico deteriorated as the economy declined. Illiteracy was high; malnutrition and poverty were rampant. Violent clashes broke out between desperate residents and Spanish merchants, who monopolized trade on the island.