 After the Portuguese throne was seized by Philip II in 1580, a number of Portuguese sought refuge in England.One of these refugees, Francisco Ferreira, piloted two English ships to the Gambia in 1587 and returned with a profitable cargo of hides and ivory.In 1588, António, Prior of Crato, who had a claim to the throne of Portugal, sold to London and Devon merchants the exclusive right to trade between the Rivers Senegal and Gambia.