Fort Matanzas
Guarding St. Augustine's Back Door
The name Fort Matanzas carries a genuinely somber history behind it. In 1565, Spanish forces under Pedro Menéndez de Avilés, founder of St. Augustine, killed several hundred French Huguenot soldiers along the shores of this same inlet, following the wreck of their fleet in a hurricane. The Spanish afterward named both the fort and the inlet “Matanzas,” the Spanish word for slaughters — a name that endured across the nearly two centuries that followed, long after the fort itself finally rose on the site.
This article, continuing Fort Pillar II's exploration of Florida's Spanish and Colonial forts, turns to the smaller sister fortification that guarded St. Augustine's vulnerable southern water approach — the genuine “back door” the much larger Castillo de San Marcos, discussed in this section's opening article, could not cover alone.
A Watchtower Finally Replaced by Stone
For nearly two hundred years after the 1565 events, only a simple wooden watchtower guarded the Matanzas Inlet, unarmed and prone to rotting quickly in Florida's warm, wet climate. That thin defense proved genuinely inadequate in 1740, when James Oglethorpe, the British governor of Georgia, led a thirty-nine-day siege of St. Augustine, using the very inlet Fort Matanzas would eventually guard to blockade the city and cut off Spanish supply ships. St. Augustine survived the siege, but Spanish colonial governor Manuel de Montiano recognized immediately that the inlet itself needed real, permanent protection.
Montiano ordered engineer Pedro Ruiz de Olano, who had already worked on additions to the Castillo de San Marcos, to design and build a proper stone tower on the site. Construction began in 1740 and finished in 1742, using coquina quarried elsewhere and ferried to the marshy building site, where workers drove long pine pilings deep into the ground to keep the fortress from sinking into the wetland. According to multiple historical accounts, the labor force included convicts, enslaved people, and troops brought specifically from Cuba to complete the demanding work.
A Small Fort Defended by a Notable Commander
Fort Matanzas was genuinely modest in scale compared to its famous sister fortress — a square measuring just fifty feet to a side, topped by a thirty-foot tower, with a standard garrison of only one officer, four infantrymen, and two gunners rotating in from regular duty in St. Augustine. Despite its small size, the fort proved its worth almost immediately: when Oglethorpe returned with twelve ships in 1740, a scouting vessel he sent toward the inlet was driven off by the fort's guns before construction had even finished, and the British fleet soon withdrew entirely. Historical records indicate this was the only occasion Fort Matanzas ever actually fired on an enemy.
Among the notable figures connected to the fort's defense was Jorge Biassou, described by Florida Memory as the nation's first Black general, who arrived in St. Augustine from Saint-Domingue, present-day Haiti, in 1796 as an officer of the Spanish militia. Biassou was placed in command of the free Black militia unit that guarded the fort's southern approach — a genuine continuation of the same tradition of Black military service in Spanish Florida already established at the Castillo de San Marcos decades earlier, discussed in the previous article in this section.
Why This Mattered for Florida
Fort Matanzas demonstrates a genuinely important defensive principle this pillar's earlier articles have already introduced: a single fort, however strong, could never fully protect a city on its own. St. Augustine's real security depended on two coordinated fortifications working together, one guarding the main harbor and one guarding the back-door water route that could otherwise bypass the city's primary defenses entirely. Understanding Fort Matanzas alongside the Castillo de San Marcos completes a fuller picture of how Spanish colonial Florida actually organized its coastal defense — not as a single fortress, but as a genuine, coordinated system.
Did You Know?
- Fort Matanzas fired on an actual enemy vessel only once in its entire history, driving off a British scouting ship in 1740.
- Jorge Biassou, described as the nation's first Black general, commanded the free Black militia unit that guarded Fort Matanzas beginning in 1796.
- The name “Matanzas” comes from a 1565 event, nearly two centuries before the stone fort itself was ever built.
Vocabulary
- Blockade — a military tactic of using ships to seal off a port or waterway, preventing supplies from reaching it.
- Piling — a long, sturdy post driven into soft or marshy ground to provide a stable building foundation.
- Garrison — the group of soldiers stationed at and responsible for defending a particular fort.
Discussion Questions
- Why might St. Augustine have needed two separate forts rather than relying on the Castillo de San Marcos alone?
- What does Jorge Biassou's command of Fort Matanzas's militia suggest about military opportunity in Spanish colonial Florida?
Quick Facts: Fort Matanzas
| Construction period | 1740–1742 |
|---|---|
| Fort dimensions | 50 feet per side, 30-foot tower |
| Standard garrison | 1 officer, 4 infantrymen, 2 gunners |
| Original cannon count | 5 (four 6-pounders, one 18-pounder) |
| Designated a National Monument | 1924 |
| Times the fort fired on an enemy | 1, in 1740, against a British scouting ship |
Related Articles on Florida Learning Hub
Sources & Further Reading
- National Park Service. “Park Archives,” Fort Matanzas National Monument. npshistory.com.
- EBSCO Research Starters. “Fort Matanzas National Monument.” ebsco.com.
- Britannica. “Fort Matanzas National Monument.” britannica.com.
- Visit St. Augustine. “Fort Matanzas National Monument.” visitstaugustine.com.
- Florida Memory, State Archives of Florida. “Fort Matanzas” and “Historic Salcedo House as the Candy Kitchen.” floridamemory.com.