the previously peaceful southern provinces to join the rebellion. The Spanish chose the route of negotiation, and pacified most of the southern provinces again with the Union of Arras in 1579. The Arras agreement required all Spanish troops to leave these lands. Meanwhile, Philip had his eye on uniting the entire Iberian Peninsula under his rule, a traditional objective of Spanish monarchs. The opportunity came in 1578 when the Portuguese king Sebastian launched a crusade against Morocco. The expedition ended in disaster and Sebastian's disappearance at the Battle of the Three Kings. His aged uncle Henry ruled until he died in 1580. Although Philip had long prepared for the takeover of Portugal, he still found it necessary to launch a military occupation led by the Duke of Alva. Philip took the title of King of Portugal, but otherwise the country remained autonomous, retaining its own laws, currency, and institutions. However, Portugal surrendered all independence in foreign policy, and relations between the two countries were never warm. France formed the cornerstone of Spanish foreign policy. For 30 years after Cateau-Cambresis, it was engulfed in civil wars. After 1590, the Spanish intervened directly in France, winning battles, but failing to prevent Henry of Navarre from becoming king as Henry IV. To Spain's dismay, Pope Clement VIII accepted Henry back into the Catholic Church. To keep the Netherlands under control required an extensive occupation force, and Spain was still financially strapped since the 1576 bankruptcy. In 1584, William the Silent was assassinated by a Catholic, and the death of the popular Dutch resistance leader was expected to bring an end to the war; it did not. In 1586, Queen Elizabeth I of England, supported the Protestant cause in the Netherlands and France, and Sir Francis Drake launched attacks against Spanish merchants in the Caribbean and the Pacific Ocean, along with a particularly aggressive attack on the port of Cádiz. Philip sent the Spanish Armada to attack England. Numbering 130 ships and 30,000 men, it was led by the Duke of Medina-Sidona. The Armada's goal was to ferry Spanish troops from the Netherlands to invade England. After three days of fighting with the English fleet, the Armada withdrew and was forced to make the journey around the coast of Scotland and Ireland, many ships being wrecked by storms. Spain had invested itself in the religious warfare in France after Henry II's death. In 1589,