Discovering San Antón de Carlos: The Sixteenth-Century Spanish Buildings and Fortifications of Mound Key, Capital of the Calusa

In 1566, Pedro Menéndez de Avilés arrived at the capital of the Calusa kingdom. During that same year Menéndez issued the order to construct Fort San Antón de Carlos, which was occupied until 1569. This fort was also the location of one of the first Jesuit missions (1567) in what is now the United States. We now can confirm what archaeologists and historians have long suspected: the location of the fort and the capital of the Calusa was Mound Key (8LL2), located in Estero Bay in southwestern Florida. In this article, we present the first archaeological evidence of structures and fortifications associated with the 16th-century Spanish fort and mission of San Antón de Carlos. We conducted this work, which includes both remote sensing and excavation, in an effort to better document the history of the Calusa capital up to and including the colonial period.