Denmark-Norway also took an interest in the islands, and the Danish West India Company settled on St. Thomas in 1672 and St. John in 1694, later purchasing St. Croix from France in 1733. The islands became royal Danish colonies in 1754, named the Danish West Indian Islands (). Initially the currency was the Danish West Indian rigsdaler, replaced by the daler in 1849. The islands proved ideal for sugar plantations – sugarcane, produced by slaves from Africa, drove the islands' economy during the 18th and early 19th centuries. Other plantation crops included cotton and indigo dye. During the 17th–18th centuries, a sizable Jewish community also began to settle on the islands.