In 1588, the claimant to the Portuguese throne, António, Prior of Crato, sold exclusive trade rights on the Gambia River to English merchants. Letters patent from Queen Elizabeth I confirmed the grant. In 1618, King James I of England granted a charter to an English company for trade with the Gambia and the Gold Coast (now Ghana). Between 1651 and 1661, some parts of the Gambia — St. Andrew's Island in the Gambia River including Fort Jakob, and St. Mary Island (modern day Banjul) and Fort Jillifree — came under the rule of the Duchy of Courland and Semigallia (now in modern-day Latvia), having been bought by Prince Jacob Kettler. The colonies were formally ceded to England in 1664.