[1] His accession established the House of Braganza on the Portuguese throne, and marked the end of the 60-year-old Iberian Union by which Portugal and Spain shared the same monarch.

[4] John IV was born at Vila Viçosa and succeeded his father Teodósio II as Duke of Braganza[5] when the latter died insane in 1630.

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,[1] executed on 1 December 1640, sixty years after the accession of Philip II of Spain to the throne of Portugal.

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.

[8] Portugal signed lengthy alliances with France (1 June 1641) and Sweden (August 1641) but by necessity its only contributions in the Thirty Years' War were in the field against Spain and against Dutch encroachments on the Portuguese colonies.

[9] One famous composition attributed to him is a setting of the Crux fidelis, a work that remains highly popular during Holy Week amongst church choirs.

The doctrine had appeared in the Middle Ages and had been fiercely debated in the 15th and 16th centuries, but a bull issued in 1616 by Pope Paul V finally "[forbade] anyone to teach or preach a contrary opinion.