Portrait of John IV (1604-1656), King of Portugal and the Algarves from 1640 to 1656; Duke of Braganza (1630-1645), 1642
John IV (Portuguese: João IV de Portugal; 19 March 1604 – 6 November 1656) was the King of Portugal and the Algarves from 1640 to his death. He was the grandson of Catherine, Duchess of Braganza, who had in 1580 claimed the Portuguese crown and sparked the struggle for the throne of Portugal. John IV was nicknamed John the Restorer (João o Restaurador). On the eve of his death in 1656, the Portuguese Empire reached its territorial zenith, spanning the globe. He was one of the main forces behind the independence of Portugal after Spanish rule. John IV was born at Vila Viçosa and succeeded his father Teodósio II as Duke of Braganza when the latter died insane in 1630. He married Luisa de Guzmán (1613–1666), eldest daughter of Juan Manuel Pérez de Guzmán, 8th Duke of Medina Sidonia, in 1633. When Philip II of Portugal (III of Spain) died, he was succeeded by his son Philip III (IV of Spain), who had a different approach to Portuguese issues. Taxes on the Portuguese merchants were raised, the Portuguese nobility began to lose its influence and government posts in Portugal were increasingly occupied by Spaniards. Ultimately, Philip III tried to make Portugal a Spanish province, meaning Portuguese nobles stood to lose all of their power. This situation culminated in a revolution organized by the nobility and the bourgeoisie, executed on 1 December 1640, fifty-nine years after the accession of Philip II of Spain to the throne of Portugal. A plot was planned by several associates, known as the Forty Conspirators, who killed the Secretary of State, Miguel de Vasconcelos, and imprisoned the king's cousin, Margaret of Savoy, the Vicereine of Portugal, governing the country in the King's name. Philip's troops were at the time fighting the Thirty Years' War and also dealing with a revolution in Catalonia which severely hampered Spain's ability to quash the rebellion. Within a matter of hours and with popular support, John, then the 8th Duke of Braganza, was acclaimed as King John IV of Portugal (as legend goes, with the persuasion of his wife) claiming legitimate succession through his grandmother Catherine, Duchess of Braganza. The ensuing conflict with Spain brought Portugal into the Thirty Years' War as, at least, a peripheral player. From 1641 to 1668, the period during which the two nations were at war, Spain sought to isolate Portugal militarily and diplomatically, and Portugal tried to find the resources to maintain its independence through political alliances and maintenance of its colonial income.
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