section_path: History/Iberian Union and Restoration
section_name: Iberian Union and Restoration
paragraph_text: Iberian Union and Restoration
  
  Portugal voluntarily entered a dynastic union (1580 – 1640) because the last two kings of the House of Aviz (Sebastian, King of Portugal, followed by his grand-uncle Henry, King of Portugal) died without heirs, resulting in the Portuguese succession crisis of 1580. Philip II of Spain claimed the throne, under the pretext that his mother was a Portuguese princess, Isabella of Portugal, the second child and first daughter of King Manuel I of Portugal. Philip II of Spain was accepted as Philip I of Portugal. Yet, Portugal did not lose its formal independence. Instead, a union of kingdoms was formed. But the joining of the two crowns deprived Portugal of an independent foreign policy, and led to its involvement in the Eighty Years' War between Spain and the Netherlands.
  
  War led to a deterioration of relations with Portugal's oldest ally, England, and the loss of Hormuz, a strategic trading post located between Iran and Oman. From 1595 to 1663 the Dutch Portuguese War primarily involved Dutch companies invading Portuguese colonies and commercial interests in Brazil, Africa, India and the Far East, resulting in the loss of Portugal's Indian sea trade monopoly.
  
  In 1640 John IV of Portugal spearheaded an uprising backed by disgruntled nobles and was proclaimed king. The Portuguese Restoration War ended the 60-year period of the Iberian Union under the House of Habsburg. This was the beginning of the House of Braganza, which reigned until 1910. John V saw a reign characterized by the influx of gold into the royal treasury, supplied largely by the royal fifth (tax on precious metals) from the Portuguese colonies of Brazil and Maranhão. Most estimates place the number of Portuguese migrants to Colonial Brazil during the gold rush of the 18th century at 600,000. This represented one of the largest movements of European populations to their colonies, during colonial times.