What happened
The Armada was to sweep the Channel and escort the Duke of Parma’s army from Flanders across to England. Harried up the Channel, scattered by fireships off Calais, and battered at Gravelines, it fled north around Scotland and Ireland, where storms destroyed dozens of ships; roughly a third to a half of the fleet never returned.
Background
Philip II ruled the greatest empire of the age and saw Protestant England — which had executed the Catholic Mary, Queen of Scots in 1587, backed the Dutch revolt, and unleashed Drake’s raids — as both a heretic state and a strategic threat. Drake’s 1587 attack on Cádiz had already delayed the fleet a year.
Consequences
England’s survival became Elizabethan legend, though the war with Spain dragged on until 1604 and later armadas also failed. In hindsight the campaign marked Spain’s imperial high-water mark and fed England’s self-image as a Protestant naval nation.