still unsettled, an Augustinian monk named Friar Pedro, who was taking an active part in the struggle, thought of the stratagem of driving cattle against the Spaniards so as to scatter them. Over a thousand head of cattle were quickly gathered and, by means of shouts and musket shots, driven against the enemy positions. The disconcerted Spaniards fell back and were pursued to the shore, where almost all of them lost their lives in the fighting or drowned while trying to reach their boats. This unconventional victory, the Battle of Salga Bay, proved that António could count on a good deal of local support. Battle of Ponta Delgada The next major military action did not take place until the following summer. Álvaro de Bazán, 1st Marquis of Santa Cruz, was sent in 1582, as "Admiral of the Ocean", to drive the pretender and his supporters from Angra and the Azores. Badly outnumbered, he won the Battle of Ponta Delgada on 26 July 1582, off the coast of the island of São Miguel, against a loose confederation of Portuguese, French, English, and Dutch privateers. Battle of Terceira Although António's fleet was completely defeated at the Battle of Ponta Delgada, the pretender did flee into exile in France after the battle. His supporters were subsequently defeated the following year at the Battle of Terceira, near Angra, on 27 July 1583, which allowed Philip's forces to finally occupy the Azores and complete his unification of the Crowns of Spain and Portugal. Yet, Santa Cruz, the Spanish admiral, who was acclaimed for his victories against the House of Aviz and its partisans in the Azores, recognized that England presented a grave threat to Spain's empire, and he became a zealous advocate of war with the English. A letter he wrote to Philip II from Angra do Heroísmo, on 9 August 1583, two weeks after the Battle of Terceira, contains the first definite suggestion of the formation of the Spanish Armada. It was following the events of the battle of Terceira that the existing fortifications in Monte Brasil were rethought. During the Anglo-Spanish War (1585–1604), the original Portuguese fortifications were redesigned by Italian military engineer Giovanni Vicenzo Casale and his assistants, since privateers, such as Francis Drake and Walter Raleigh, had attacked Spanish ships and possessions. The first cornerstone was laid in 1583, and the fortifications were progressively elaborated to include several bastions and cannon