From the 1570s, the lengthy Dutch Revolt increasingly challenged Spanish sea power, producing powerful rebel naval forces that attacked Spanish shipping and in time made Spain's sea communications with its possessions in the Low Countries difficult. Most notable of these attacks was the Battle of Gibraltar in 1607, in which a Dutch squadron destroyed a fleet of galleons at anchor in the confines of the bay. This naval war took on a global dimension with actions in the Caribbean and the Far East, notably around the Philippines. Spain's response to its problems included the encouragement of privateers based in the Spanish Netherlands and known from their main base as Dunkirkers, who preyed on Dutch merchant ships and fishing trawlers.