The defeat of the Spanish Armada in 1588 was the greatest feat of English arms since the Battle of Agincourt a century and a half earlier. The poorly planned expedition with its huge galleons was ordered to join with the Spanish Army in the Netherlands for an invasion of Queen Elizabeth I's Protestant England. But the Spaniards found that the English had radically changed the rules of sea warfare, with a new breed of warship employing newly-devised techniques of gunnery which thwarted the Armada as it fought its way up the Channel.