Du Croix was originally settled by the Nbele peoples of Greater Azores in the 1070's. Plagues around 1370 and 1415 killed all the natives that had not left.
It was settled in 1608 by the French as a prison island for convicted prisoners. There were terrible conditions and many plagues. There were few guards, and the island was mostly patrolled from boats in the sea.
It was used by many years but it was shut down in 1934.