Barbados is a coral island, which was already known to the Spanish by 1500. A Portuguese mariner named Pedro Campos landed on the island in 1536, but the first English colonist to land on the island was Captain Simon Gordon, in 1620. The island would not be claimed for the English crown until five years later, by Captain John Powell. Barbados began as a slave colony, but slavery in this English settlement began its existence completely by accident. The number of African slaves remained minimal, until the success of sugarcane cultivation caused the demand for field workers to drastically increase.