1. All previous attempts to settle Florida had ended disastrously.

From 1513 to 1559, the Spanish sent several major expeditions to Florida, but each one ended in complete failure. Juan Ponce de León’s colonization attempt, for example, was cut short by a Native American arrow that mortally wounded him, whereas Hernando de Soto died of disease after three years of aimless wandering. Meanwhile, the first known European settlement in the continental United States, founded by Lucas Vázquez de Ayllón in 1526 in what’s believed to be present-day Georgia, was abandoned after just a few months. Another Spanish settlement, founded in 1559 in present-day Pensacola, Florida, didn’t do much better, lasting less than two years. Upon hearing news of this latest disappointment, an exasperated King Philip II of Spain put a stop to all further efforts to colonize Florida.

2. St. Augustine’s primary purpose was to thwart the French.

Philip II changed his mind, however, once French Protestants (known as Huguenots) built Fort Caroline in present-day Jacksonville. Intent on ousting them, the king dispatched Menéndez across the Atlantic Ocean in the summer of 1565. Marching north in a rainstorm within days of founding St. Augustine, he and 500 men easily overran the fort and butchered most of its male inhabitants. Menéndez then learned that a number of French boats had shipwrecked while chasing his flagship down the coast. Though the castaways surrendered without a fight, the Spanish tied them up and brutally stabbed them to death. A second group of French castaways was similarly massacred two weeks later. Ever since, that site south of St. Augustine has been called Matanzas (Spanish for “Slaughters”). In 1568, French privateers and their Native Americans allies took revenge by destroying Fort Caroline—which had been renamed Fort San Mateo—but never again would France establish a foothold in the area.

3. St. Augustine has been attacked numerous times.

Like everywhere they landed, the Spanish at St. Augustine constantly clashed with the local Native Americans, who once purportedly set the city’s fort on fire with flaming arrows. Just as these skirmishes were finally dying down, English privateer Sir Francis Drake arrived in 1586 with 2,000 men. As the residents of St. Augustine hid in the woods nearby, Drake’s force burned their houses and crops, took whatever plunder they could find and then sailed away. English buccaneers ransacked the city again in 1665, and in 1702 and 1740 it survived destructive sieges initiated by the governors of Carolina and Georgia, respectively. Yet another incursion took place in 1812, when a band of militiamen arrived as part of an ill-conceived bid to annex Florida to the United States. A half-century later, during the early stages of the Civil War, St. Augustine surrendered peacefully to the Union navy.

4. Slaves were encouraged to flee there.

Racial mores weren’t nearly as rigid in Spanish Florida as they were in the British colonies to the north. In fact, to counter his country’s numerical disadvantage in the region, King Charles II of Spain proclaimed in 1693 that runaway slaves from British lands would be given their freedom in Florida provided they converted to Catholicism. Forty-five years later, Florida’s governor approved a settlement for ex-slaves just to the north of St. Augustine. Called Fort Mose, it was the first legally sanctioned free black town in North America. During the many British colonial attacks on St. Augustine, blacks generally stood side-by-side with Native Americans and white Spaniards in defending the city.

5. The English briefly controlled St. Augustine.

Britain reigned supreme in North America in 1763, having wrested away Canada from the French and Florida from the Spanish in the Seven Years’ War. To British officials, St. Augustine failed to make much of a first impression. One army officer called it nearly devoid of all food except fish and “overgrown with weeds.” Yet at that point, it was the most cosmopolitan locale around. During their tenure, the British divided the colony into East Florida, with its capital in St. Augustine, and West Florida, with its capital in Pensacola. They didn’t have time for much else, however, because they were forced to return the Floridas to Spain in 1784 as part of the same treaty that granted the American colonies their independence.

6. The city was a refuge for loyalists during the Revolutionary War.

Alone among the colonies in the present-day United States, the Floridas remained loyal to Britain during the American Revolution. Residents of St. Augustine even burned effigies of John Hancock and Sam Adams in protest of the Declaration of Independence. Thousands of loyalists fled there over the course of the war, including military commander Thomas Brown, who arrived after being tarred, feathered and beaten by Sons of Liberty members in 1775. He would go on to lead a militia, the so-called East Florida Rangers, in numerous battles against the colonists.

7. St. Augustine’s fort served as a prison for captured Native Americans.

Spain ceded Florida to the United States in 1821. Not long afterwards, the U.S. government called for the removal of all Seminoles to Indian Territory west of the Mississippi River, thus precipitating the Second Seminole War. Unfamiliar with the swampy terrain and unaccustomed to the brutal heat, U.S. troops suffered one humiliating defeat after another early in the conflict. They therefore resorted to trickery, seizing Seminole leader Osceola and about 70 warriors by luring them in under a white flag of truce. The captives were marched seven miles northeast to St. Augustine, where they were stashed at Fort Marion, a structure first built by the Spanish in the late 1600s. Twenty Seminoles engineered a daring escape by squeezing through a small hole near the roof and falling into the moat below. But not Osceola, who fell ill and died upon being transferred to a jail in South Carolina. Decades later, Fort Marion likewise held Comanche, Cheyenne, Apache and other Native American prisoners of war from out West, including Geronimo’s wives and children.

8. The city was a key location in the civil-rights movement.

In 1964, as St. Augustine prepared to celebrate its 400th anniversary, Martin Luther King Jr. and other civil-rights activists descended on the city in support of an ongoing local campaign to end racial segregation there. The Ku Klux Klan and other whites responded violently, severely beating several of the activists, constantly insulting and heaving projectiles at them, and setting a car and home on fire. The owner of a whites-only pool even used acid to dislodge a mixed-race group that had jumped in. Meanwhile, King was arrested for trying to eat in a segregated restaurant, and the house he was supposed to stay in was strafed with gunfire. Yet although many of King’s goals went unfulfilled, such as the formation of a biracial committee to address discrimination in St. Augustine, the hard work nonetheless paid off. In part due to the national attention the protests received, the Senate voted to end an 83-day filibuster of the Civil Rights Act. King and his compatriots left town on July 1, the day before President Lyndon B. Johnson signed the landmark anti-segregation bill into law.