The location of Fort San Antón de Carlos, home to one of the first Jesuit missions in North America, has been discovered by archaeologists. The Spanish fort was built in 1566 in the capital of Calusa, the most powerful Native American tribe in the region, on present-day Mound Key in the center of Estero Bay, on the Florida Gulf Coast. Archaeologists and historians have long suspected that the fort, named for the Catholic patron saint of lost things, was located on Mound Key. Investigators have been searching for tangible evidence in the area since 2013.
“Before our work, the only information we had was from Spanish documents, which suggested that the Calusa capital was on Mound Key and that Fort San Antón de Carlos was there, too,” explained William Marquardt, curator emeritus of South Florida archaeology and ethnography at the Florida Museum of Natural History.
“Archaeologists and historians had visited the site and collected pottery from the surface, but until we found physical evidence of the Calusa king’s house and the fort, we could not be absolutely certain.”
The Calusas were one of the world’s most complex hunter-gatherer groups and resisted European colonization for nearly 200 years, Marquardt revealed, adding that the Calusa natives are often considered the earliest “shell gatherers,” who use shells as tools, utensils, and jewelry, and dispose of the shards in huge mounds. They also built massive structures known as watercourses, which acted as fish corrals, providing food to fuel large-scale construction projects and a growing population.
The Calusa controlled most of southern Florida before being crushed by European diseases. Investigators believe that when the Spanish handed Florida over to the British, any remaining Calusa had already fled to Cuba.
Researchers continue to investigate how the Spanish survived on Mound Key and covered their daily needs despite unreliable shipments of minimal supplies from the Caribbean and strained relations with the Calusa, whose surplus supplies they needed to survive. The only Spanish fort known to have been built on a shell mound, Fort San Antón de Carlos, is thought to have abandoned in 1569 after the brief Spanish alliance with the Calusa deteriorated, causing the Calusa to abandon the island, and the Spanish followed soon after.
“Despite being the most powerful society in South Florida, the Calusa were inexorably drawn into the broader world economic system by the Spaniards,” Marquardt revealed.
“However, by staying true to their values and way of life, the Calusa showed a resiliency unmatched by most other Native societies in the Southeastern United States.”
Scientists from the University of Florida, the University of Georgia, and students from UGA’s archaeological field school used a mixture of remote sensing, coring, ground-penetrating radar, and excavations to reveal the walls of the fort and a few artifacts, including ceramic sherds and beads.
As revealed by scientists, the discovery of the front also marks the finding of the earliest-known North American example of “tabby” architecture, a rough form of shell concrete. “Tabby,” also called “tabbi” or “tapia,” is made by burning shells to create lime, which is then mixed with sand, ash, water, and broken shells, the researchers revealed.
Curiously, several thousand years before the Calusa even appeared in history, at a time when even the Egyptian pyramids did not exist, Brazilian Natives erected massive structures out of seashells. These massive seashell mounds are acknowledged by archeologists as the oldest known pyramids on the surface of the planet.
According to archaeological surveys of parts of present-day Brazil, the ancient Natives erected thousands of pyramids across Brazil, some of which date back around 5,000 years. All of the Brazilian pyramids were built with seashells as the main construction material.
The discovery is detailed in a study published in the Jornal Historical Archaeology.