The auction house has revealed documents from 1588 appointing Duke Dom Alonso Pérez de Guzmán as the head of the expedition following the death of the Marquis of Santa Cruz. These documents also provide detailed military instructions concerning the voyage, coordination with the Duke of Parma’s army in Flanders, and alternative actions in case of setbacks.
The Spanish Armada was a fleet sent by Philip II during the Anglo-Spanish War (1585-1604) with the aim to invade England, overthrow Elizabeth I, restore Catholicism, curb English support for the independence of the Netherlands—then under Spanish rule—and halt piracy attacks on Spanish routes and colonies.
The documents also included a secret instruction contemplating the capture of the Isle of Wight and the capture of the Portuguese throne claimant, Dom António.
Dom António, Prior of Crato, who lived from 1531 to 1595, was a grandson of King D. Manuel I and presented himself as a candidate for the Portuguese throne in 1580, after the disappearance of King D. Sebastião in the Battle of Alcácer Quibir in 1578.
An order signed by Medina Sidonia aboard the galleon San Martín was also included, giving directions on naval combat, safety, and discipline on board.
These letters, previously held privately, provide valuable insights into the preparations for one of the largest naval operations of the 16th century, which ended in a notable defeat for Spain due to a combination of military, strategic, weather, and logistical factors.
