United States Virgin Islands History, a Travel Guide. The Journey to the Island, Inhabitant's. Root, Culture and tradition. After dividing the islands into plantations, the Danes began growing sugarcane, first using convicted criminals and then, after 1673, African slaves for labour. Commerce developed from the triangular trade in slaves brought from Africa, rum and molasses sent to Europe, and European goods shipped back to the islands. St. Thomas became a major slave market for the Caribbean. Denmark purchased St. Croix in 1733, and it became a major centre of sugarcane production.