Dunkirkers

During the Dutch Revolt (1568–1648), the Dunkirkers or Dunkirk Privateers were commerce raiders in the service of the Spanish monarchy. They were also part of the Dunkirk fleet, which consequently was a part of the Spanish monarchy's Flemish fleet (Armada de Flandes). The Dunkirkers operated from the ports of the Flemish coast: Nieuwpoort, Ostend, and Dunkirk. Throughout the Eighty Years' War, the fleet of the Dutch Republic repeatedly tried to destroy the Dunkirkers. The first Dunkirkers sailed a group of warships outfitted by the Spanish government, but non-government investment in privateering soon led to a more numerous fleet of privately owned and outfitted warships.

Dunkirk was in the hands of the Dutch rebels from 1577 until 1583, when Alexander Farnese, Duke of Parma re-established the sovereignty of his uncle Philip II of Spain as count of Flanders. Dunkirk was, at the time, an important, strategically positioned port with its approaches shielded by sandbanks. In 1583, Parma assembled a small royal squadron of warships to destroy Dutch naval trade and fisheries. However, it did not take long before the Habsburg authorities in the Low Countries began issuing letters of Marque, and privately owned warships filled the ranks of the Dunkirkers. These privately owned warships were known in Dutch as the particulieren, to distinguish them from the royal warships that were also part of the fleet. At their peak, the Dunkirkers operated about a hundred warships. The crews were mostly made up of Flemish fishermen, supplemented with Walloons, Spaniards and many individuals from the Northern Netherlands and other European countries. Apart from targeting trade and fishing, the royal squadron was often used to convoy troops between Spain and the Spanish Netherlands.

...
Wikipedia