Castillo de San Marcos, Florida

Location: 11 South Castillo Dr, St. Augustine, Florida    Map

Constructed: 1672

 

Description

Castillo de San Marcos or Castle of Saint Mark is situated at 11 South Castillo Dr, St. Augustine, Florida in United States. The city of San Agustín was founded by Spain in 1565. During its first century of existence, nine wooden forts defended the position. After the attack of the English pirate Robert Searle in 1668, it was decided to build a stone castle to protect the city. The construction of Castillo de San Marcos began on October 2, 1672 by the Spanish army when it was part of the Spanish Empire.
 
Castillo de San Marcos is a star shaped fortification built with coquina, a variety of limestone. The workers were brought from Havana, Cuba. The coquina was extracted from Anastasia Island, on the other side of the bay, and taken on boats to the construction site. In 1695, after twenty-three years of hard work, the fortress was ready.

 

History

Spain founded St. Augustine in 1565 under Pedro Menéndez de Avilés, the first permanent European settlement in what is now the United States. For over a century, the town relied on nine successive wooden forts for defense against pirates, privateers, and rival European powers. A devastating raid in 1586 by Sir Francis Drake burned much of the settlement. The decisive trigger came on May 28, 1668, when English privateer Robert Searles (also known as John Davis) sacked St. Augustine, looting and burning the town while the wooden fort offered little protection. This raid, combined with the recent English founding of Charles Town (Charleston) in 1670—just a short sail away—convinced Spanish authorities that a permanent stone fortress was essential to protect Florida, the treasure fleets, and Spanish claims in the New World. Queen Regent Mariana of Spain approved funding, and construction was ordered after the raid.

Construction (1672–1695) and the “Rock That Saved St. Augustine”
Governor Manuel de Cendoya oversaw groundbreaking on October 2, 1672 (under the design of Spanish engineer Ignacio Daza). The project took 23 years and cost enormous sums, funded by the Spanish crown and New Spain (Mexico). Laborers included Native Americans from nearby missions, enslaved Africans, convicts, and skilled masons from Havana. Over 75,000 tons of stone were quarried.
The material chosen was coquina (“tiny shell” in Spanish), a porous limestone formed from ancient coquina clam shells cemented by calcium carbonate during the last ice age. Quarried on Anastasia Island (just across Matanzas Bay), it was the only local stone available. Engineers initially doubted its strength and built walls extraordinarily thick—averaging 12 feet (up to 19 feet on the seaward side)—using oyster-shell lime mortar. Unexpectedly, coquina proved brilliantly effective: its millions of microscopic air pockets allowed it to compress and absorb cannonball impacts like a sponge, causing balls to embed or bounce off rather than shatter the wall (unlike brittle granite or brick). This property would save the fort repeatedly.

Design and Architecture: A Vauban-Style Masterpiece
The Castillo is a classic example of 17th-century European bastion fortifications (influenced by French engineer Vauban). Its star-shaped layout features four diamond bastions (San Pedro, San Agustín, San Carlos, San Pablo) connected by curtain walls, a ravelin protecting the sally port (main gate), a dry moat (floodable with seawater), and a glacis (sloped earthwork) that forced attackers uphill into cannon fire. Embrasures allowed cannons on the terreplein (gun deck) and muskets below. The design maximized crossfire while minimizing blind spots, making direct assault nearly impossible. It could shelter over 1,500 people and withstand prolonged sieges.

Colonial Sieges: Proof of Strength (1702 and 1740)
The fort faced its greatest tests during Anglo-Spanish wars.

Siege of 1702 (Queen Anne’s War / War of the Spanish Succession): English forces from Carolina under Governor James Moore (~1,500 men, nine ships, Native allies) attacked in November–December. About 1,500 Spanish civilians and soldiers sheltered inside. English cannons and mortars proved useless against coquina walls. A Spanish relief fleet from Havana arrived on December 26; Moore burned his ships and retreated overland, partially destroying the town but failing to take the fort.
Siege of 1740 (War of Jenkins’ Ear): British General James Oglethorpe (Georgia founder) led a larger force with naval support. He bombarded the Castillo for 27–29 days from May to July. Again, coquina absorbed the punishment—“as though you would stick a knife into cheese.” Spanish repairs at night, privateers, and a threatened Cuban relief force forced Oglethorpe’s retreat due to supply shortages and disease. The fort stood unbreached.

In its entire history under multiple flags, the Castillo was never captured by assault—only transferred by treaty.

Ownership Changes: Five Peaceful Transfers
First Spanish Period (1695–1763): Primary defensive stronghold.
British Period (1763–1783): Ceded via Treaty of Paris after the Seven Years’/French and Indian War. Renamed Fort St. Mark. Used as barracks, supply depot, and prison during the American Revolution (holding Declaration of Independence signers and patriot Christopher Gadsden). St. Augustine became a Loyalist haven.
Second Spanish Period (1783–1821): Returned via Treaty of Paris after the American Revolution. Minor maintenance only.
U.S. Period (1821–present): Acquired via Adams-Onís Treaty. Renamed Fort Marion in 1825 after Revolutionary War hero Francis Marion. Served as coastal defense, barracks, and notably a military prison.

During the Civil War (1861–1865), Confederates briefly held it without combat; it returned to Union control.

Prison Years Under U.S. Control (19th Century)
After its defensive role ended, Fort Marion became a notorious prison:
Seminole Incarceration (1837, Second Seminole War): Following the Indian Removal Act, over 230 captured Seminoles (including war leader Osceola and Coacoochee/Wild Cat) were imprisoned here after a deceptive truce. Conditions were harsh (crowded cells, illness). On November 29, 1837, Wild Cat and ~19 others escaped through a high embrasure using a rope, prolonging the war. Osceola was later transferred and died at Fort Moultrie. Many Seminoles trace heritage to these “Unconquered” escapees.
Plains Indians (1870s): ~74 Cheyenne, Arapaho, Kiowa, Comanche, and Caddo prisoners were held. They created famous “ledger art” (drawings on ledger paper) depicting their lives and battles—now a significant Native artistic legacy.
Apache Prisoners (1886–1887): Over 500 Chiricahua and Warm Springs Apache (including some from Geronimo’s band) were imprisoned here after surrender. At least 24 died; their remains were later repatriated.

These uses reflect the fort’s shift from protector to instrument of U.S. Indian policy.

20th Century to Present: Preservation and National Monument
Decommissioned as a military site in 1899, it was designated a National Monument in 1924 (as Fort Marion), transferred to the National Park Service in 1933, and officially restored to its original Spanish name Castillo de San Marcos by an Act of Congress in 1942 to honor its history. Minor restorations and preservation work continue (e.g., cannon conservation). In 1964, the grounds hosted civil rights gatherings. Today it draws hundreds of thousands of visitors annually, interpreting Spanish colonial, Native American, African American, and American stories. It is also a Historic Civil Engineering Landmark.

 

Architecture

Overall Layout and Star-Shaped Bastion Design
The fort centers on a nearly square plaza (sides measuring approximately 320 feet) with four diamond-shaped (or angle-shaped) bastions projecting outward at each corner: San Pedro, San Agustín, San Carlos, and San Pablo. Each bastion features a sentry box (garita) at its tip for lookout and signaling. The curtain walls connecting the bastions are straight segments pierced by embrasures (openings) for cannons and muskets.
This star-shaped plan—originating in 15th-century Italy and refined in the Vauban style—eliminates "dead zones" or blind spots. Geometric principles ensure that cannons on any bastion or curtain wall can enfilade (rake with crossfire) attackers approaching any face or corner. The bastions allow overlapping fields of fire: an enemy assaulting one wall comes under direct or angled fire from adjacent bastions.

Materials and Construction Techniques: The Role of Coquina
The fort's walls and structures use coquina, a rare porous limestone formed from compressed seashells (primarily coquina clams) quarried on nearby Anastasia Island. Blocks were cut by hand—over 400,000 in total—and laid with mortar made by burning oyster shells into lime, then mixing with sand and water. The exterior was originally coated with lime stucco for weather protection and a smoother finish.
Coquina's physical properties make it uniquely suited (and ironically ideal) for fortifications despite its softness: it contains millions of microscopic air pockets, making it compressible like Styrofoam. Cannonballs burrow into or embed in the stone rather than shattering it, absorbing impact energy. Walls average 12 feet thick (up to 19 feet on the seaward side), rising 30 feet high (base 10–14 feet thick, tapering to 5 feet at the top). This "forgiving" material withstood prolonged British bombardments in 1702 and 1740 without breaching.
Construction progressed slowly due to labor (Spanish artisans, convicts, Indigenous workers, and slaves) and the novelty of large-scale coquina masonry. The main block was largely complete by 1686 (outer walls in coquina, interiors initially wood), with full completion around 1695. The terreplein (gun deck) originally used wooden beams and tabby (seashell-lime concrete), but these rotted; in the 1730s–1750s, engineer Antonio de Arredondo replaced them with bomb-proof stone vaulted arches (casemates).

Defensive Features: Bastions, Gun Deck, and Outerworks
The terreplein (wide, flat gun platform atop the walls) supports heavy cannons firing through embrasures in the parapet. Lower levels include musket slots. The design integrates infantry and artillery seamlessly.

Outer defenses form a complete system:
Moat — A 42-foot-wide, coquina-lined dry ditch (originally encircling most sides; east side later filled). It could be partially flooded with seawater.
Ravelin — A triangular masonry outwork in the moat, directly protecting the south-side sally port (the fort's only entrance). It mounts its own cannons and includes a powder magazine; access is via drawbridge.
Glacis and Covered Way — A sloped earth rampart (glacis) beyond the moat forces attackers uphill, exposing them to plunging fire. The covered way (protected path between moat and glacis) allows defenders to maneuver safely.
Later additions (18th–19th centuries) include the Cubo Line palisade, City Gate, seawall, and east-side water battery for harbor defense.

Interior Architecture and Functional Spaces
Inside the plaza (parade ground) are vaulted casemates—arched, bomb-proof rooms beneath the terreplein—used for troop quarters, a chapel, storerooms, wells, ovens, and a powder magazine. These were enlarged and arched in the 1730s–1750s for strength and habitability (original flat wooden ceilings failed under the weight of guns and weather). The sally port leads into this courtyard via drawbridge from the ravelin.

Evolution, Modifications, and Architectural Significance
Early plans (1675) show a simpler version; by 1763 the vaults, taller walls (raised ~5–7 feet), and completed ravelin/glacis were in place. British and U.S. periods added minimal changes (e.g., water battery in the 1840s), preserving the Spanish core. The fort was never taken by direct assault, proving the effectiveness of its design and materials.
As the sole extant example of 17th-century bastioned masonry in the U.S.—and one of only two coquina forts worldwide (with nearby Fort Matanzas)—it bridges medieval castles and modern coastal defenses. Its adaptation of European engineering to local resources and colonial threats makes it a masterpiece of military architecture and a testament to Spanish colonial ingenuity.

 

Haunted legends

The Star-Crossed Lovers (The Woman in White or Perfume Ghost)
One of the most romantic and tragic tales involves Colonel García Martí (or Garcia Marti), commander in the late 1700s (around 1784 when Spain regained the fort). He brought his young, vivacious wife Dolores (sometimes linked to or confused with Maria Mancilla in variants). Dolores befriended (and allegedly romanced) the colonel's aide, Captain Abela (or a young officer named Manuel in other tellings). The colonel noticed her perfume on the captain's uniform, exposing the affair.
According to legend, Martí had the lovers secretly chained and walled up alive in a hidden dungeon chamber (or immured in a storage room). He claimed they had been sent away—Abela to Cuba, Dolores to Mexico. Decades later (around 1833 in some accounts), a curious soldier or architect discovered the hollow wall, revealing two chained skeletons and a lingering sweet perfume.
Hauntings: Dolores appears as a "Woman in White" (or flowing blue gown in some versions) gliding through corridors and ramparts, whispering or calling out. Visitors report her perfume wafting in the secret room or near dungeons, shadowy figures of a young couple, anguished whispers, and a sense of sorrow. A related "Screaming Woman" legend may tie in—her cries echo in coquina halls at dawn or dusk, possibly from betrayal or unjust imprisonment. A young man's apparition sometimes stands on the ramparts gazing seaward. Some sources describe them as eternally seeking each other.

Spectral Spanish Soldiers and the Lost Company
Spanish colonial troops dominate sightings. The most specific is Captain Domingo Martinez, who died defending the fort during the 1702 British siege (Queen Anne's War). He appears solid on the gun deck at sunset—uniformed, casting shadows, overlooking Matanzas Bay—accompanied by phantom commands, gunpowder smells, and leather. Rangers and visitors have tried speaking to him before he vanishes.
Broader apparitions include Spanish sentries (the "Phantom Watchmen") marching ramparts or running hallways, shadowy figures in watchtowers, and cannon crews. Sounds of drills, artillery, or battle shouts arise on quiet nights or during thunderstorms.
The eerie Lost Company legend: In 1784 (during renovations), a group of Spanish soldiers was accidentally sealed alive in a storage room. Discovered years later as skeletons still clutching weapons, their collective spirit now marches in formation through corridors—especially pre-dawn—sounding like multiple boots on stone.
Experiences: Full-body apparitions on battlements, electronic malfunctions near trauma sites, and security footage of period-dressed figures in off-limits areas.

Seminole and Native American Spirits (Including Osceola)
The fort imprisoned hundreds of Native Americans during the Seminole Wars (1830s–1850s, as Fort Marion). Conditions were brutal: windowless cells, disease, and death far from home.
Chief Osceola (captured 1837 under truce flag) is central. Legends claim his spirit lingers in the northwest bastion or courtyard—proud in traditional dress, radiating dignity and sadness. Some describe a floating head or headless warrior searching for his stolen head (historically removed post-mortem by a doctor at Fort Moultrie, SC, where he actually died in 1838; the fort's legend adapts this). He reportedly communicates telepathically with visions of his people's suffering and U.S. betrayal.
Other Seminole prisoners appear as shadowy figures or a leaping apparition jumping from high walls (symbolizing escape attempts). A general "headless chief" or soldier paces ramparts. Visitors feel overwhelming sadness and dread in dungeons, where Native ghosts are sensed.

Dungeon Hauntings: Prisoners, the Warden, and Screams
The subterranean casemates/dungeons housed British prisoners (Queen Anne's War), Confederates (Civil War), pirates, and Natives. Many died in chains from disease or cruelty.
Phenomena: Cold spots (drops of 15–20°F), rattling chains in empty cells, pleading voices, moans, EVPs in Spanish, and an oppressive "watched" feeling. A "stern Warden" apparition in colonial uniform patrols, keeping order. One psychic reportedly suffered a physical attack by a prisoner's spirit during an investigation.
Specifics include British pirate Andrew Ransen (executed here) and anonymous Confederate/British souls. A "ghostly figure jumping from walls" or phantom lights in the watchtower add to the dread.

Other Phenomena and General Activity
Headless Soldier: Paces ramparts, evoking battle executions.
Phantom lights from the watchtower, like ghostly patrols.
Indentations on old cots (as if someone lies there), pushes near powder rooms, and bootsteps in empty halls.
Activity peaks at night; thunderstorms trigger "cannon fire" echoes.

The fort's thick coquina walls are said to "trap" energy from centuries of conflict, imprisonment, and betrayal.

Visiting Tips: Explore daytime via NPS tours for history, then join evening ghost tours (e.g., from Ghost City Tours, Ghosts & Gravestones, or St. Augustine Ghost Tours) for legend-focused access. Paranormal investigations require permits. Bring cameras for orbs; expect battery drain and chills. The site is family-friendly by day but eerie after dark.