Joost van Trappen with his family and an African domestic slave. Anonymous, c. 1635. Many of the merchants and seamen based in Zeeland were involved in privateering and slavetrading in the Atlantic. As vice-admiral, Joost van Trappen, known as Joost Banckert (1599-1647), sailed under the command of Piet Heyn when the latter captured the Spanish treasure fleet in 1628. A year later he took part in the capture of the city of Recife on Brazil's northeastern coast.