Ignored by Spanish explorers, who found the region too hot and poor to be claimed, the region was not colonized until 1604, when a French settlement was founded.  However, it was soon destroyed by the Portuguese, who were determined to enforce the Treaty of Tordesillas.  French colonists returned in 1643 and founded Cayenne, but they were forced to leave once more following Amerindian attacks.  In 1664, France finally succeeded at establishing a permanent settlement at Cayenne.  Over the next decade the colony changed hands between the French, Dutch, and English, before being restored to France.  It was captured by an Anglo-Portuguese force during the invasion of Cayenne in 1809 and administered from Brazil until 1814, when it was returned to French control.  It was used as a French penal colony from 1854 to 1938.