The Duchy of Courland probably was the smallest country taking part in colonization of Caribbean. The Duchy of Courland and Semigallia existed in the western part of present-day Latvia from 1561 until 1795. Under the rule of Duke Jacobus Kettler (1642–1682) the Duchy reached the peak of its prosperity. Duke Jacobus strongly believed in the economic theory of Mercantilism and enthusiastically supported colonial ventures. In 1651 the Duchy gained its first colony, Fort Jacob, on St. Andrews Island in the Gambia River in West Africa. Later he established a more important colony on the island of Tobago in the Caribbean, existing first from 1654 to 1659 and then intermittently from 1660 to the 1690s.