The Spanish Armada (Spanish: Grande y Felicísima Armada "Great and Most Fortunate Navy" or Armada Invencible, "Invincible Navy") is the Spanish fleet that sails against England under the command of the Duke of Medina Sidonia in 1588, leading to the Norris-Drake Expedition or English Armada of 1589.King Philip II of Spain has been king consort of England until the death, in 1558, of his wife, Queen Mary I of England, and he takes exception to the policies pursued by her successor, his sister-in-law Elizabeth I.

The aim of his expedition is to invade and conquer England, thereby suppressing support for the United Provinces – that part of the Spanish Netherlands in possession of the Dutch rebels – and cutting off attacks by the English against Spanish possessions in the New World and against the Atlantic treasure fleets.

The king is supported by Pope Sixtus V, who treats the invasion as a crusade, with the promise of a further subsidy should the Armada make land.

The Armada's appointed commander is the highly experienced Álvaro de Bazán, but he dies in February 1588, and Medina Sidonia takes his place.

The fleet sets out with 22 warships of the Spanish Royal Navy and 108 converted merchant vessels, with the intention of sailing through the English Channel to anchor off the coast of Flanders, where the Duke of Parma's army of tercios will stand ready for an invasion of the southeast of England.The Armada achieves its first goal and anchors outside Gravelines, at the coastal border area between France and the Spanish Netherlands.

While awaiting communications from Parma's army, it is driven from its anchorage by an English fire ship attack, and in the ensuing battle at Gravelines the Spanish are forced to abandon their rendezvous with Parma's army.The Armada manages to regroup and withdraw north, with the English fleet harrying it for some distance up the east coast of England.

A return voyage to Spain is plotted, and the fleet sails into the Atlantic, past Ireland.

But severe storms disrupt the fleet's course, and more than 24 vessels are wrecked on the north and western coasts of Ireland, with the survivors having to seek refuge in Scotland.

Of the fleet's initial complement, about 50 vessels fail to make it back to Spain.The expedition is the largest engagement of the undeclared Anglo–Spanish War (1585–1604).