The Spanish Armada was defeated in a series of engagements by a large English naval force under the command of Lord Admiral Charles Howard. Howard inflicted heavy losses on the Armada, which was actually comparable, contrary to legend, to the English fleet in terms of size. But what really doomed the invasion force was its inability to link up with a fleet under the Duke of Parma, who was supposed to sail from the Netherlands, but was unable to do so due to the ability of Dutch raiders to harass his barges and ships. Unable to find Parma, the Spanish admiral the Duke of Medina Savonia sailed his ships north, while some others in his fleet sought refuge in Ireland, where many of the Spaniards were executed by English troops or spirited away to safety by the sympathetic Irish. Much of the fleet was destroyed by storms on the return voyage. So it was a combination of poor logistics, the efforts of the English navy under Howard, and terrible weather that destroyed the Spanish Armada.
Lord Admiral Charles Howard of the English Fleet, and bad weather which played a part in the destruction of the Spanish Armada