He was a French Hugenot that made the three voyages to and from the colony at Fort Caroline in the 1560's. In spite of the fact the article says " "The inability to find the fort has made some wonder if it ever existed." There can be no legitimate wonder because of this book. It is first hand primary source.
In 1854, Kirk Monro wrote a book titled "The Flamingo Feather". As a boy, I read it over and over. It is essentially a fictional account of the events descried in "Three Voyages"
As an adult I have made numerous backpacking trips to the Cumberland Island National Sea Shore. One of the reasons I was drawn to that island was the creepy feeling that I was treading the ground described in the Flamingo Feather. I did extensive research to place Fort Caroline at the St Mary's River estuary. The St Mary's river provides the access to the great swamp the books describe. That would be the Okefenokee Swamp.
The Fort Caroline was captured and destroyed by the Spanish marching Overland from St Augistine. That fact is well known and is certain. The distance to the river of May in Florida at Jackonsville and the USNB at Mayport from St Augistine is much shorter and believable than to either Fernindina/Cumberland Island or the Altamatha River estuary.
I have no doubt there was a site discovered. I would doubt it is Ft Caroline. BTW, the Fort Caroline National Historical Park was established in 1966 on land given to the park service for the establishment of the park. There was nothing there that actually drew the park service.
