The island has no remnant of the first occupants, the Ligurians, soon to be followed by the Romans who settled there an oppidum. From the 5th century and for a thousand years, Sainte-Marguerite has belonged to the monks of Lérins. A chapel built in honor of Sainte-Marguerite will have her name.
The strategic position of the island did not escape the Duc de Guise who ordered in 1617 the construction of a defensive structure designed to lock the access to Cannes. The modest building was enlarged by the Spanish who occupied the island during the 30 year war.
The French then recaptured, and Vauban visited the island and gave instructions on how to strengthen it. The Fort Royal has changed little since these works were carried out at the end of the 17th century.
It became a State prison in 1685. The history has retained a few famous prisoners, including General Bazaine, the only one to have escaped from the fort, and the mysterious Man in the Iron Mask. Some cells can still be visited today.
