HEYN, PIETER PIETERZOON (commonly abbreviated to PIET) Dutch admiral, was born at Delfshaven in 1578. In Sept. 1628 he captured the Spanish fleet carrying bullion from the American mines. The total loss was estimated by the Spaniards at four millions of ducats. Soon thereafter Heyn was given command of the naval force of the Republic, with the rank of lieutenant admiral of Holland, in order to clear the Chan nel and the North Sea of the Dunkirkers, acting for the king of Spain in his possessions in the Netherlands. In June 1629 he severely defeated the Dunkirkers, but was killed in the fight. See de Jonge, Geschiedenis van het Nederlandsche Zeewezen; I. Duro, Armada Espanola, iv.; der Aa, Biograph. Woordenboek der Nederlanden.