Iberian Union
The Iberian Union was a state that governed the Iberian peninsula between 1580 and 1640. After the young king of Portugal and his uncle died, three of their relatives fought the War of the Portuguese Succession. Philip II of Spain won, thus linking the monarchies of Portugal and the Spanish branch of the House of Habsburg. This dynastic union joined the crowns of Castile, Portugal and Aragon along with their respective colonial possessions, under the rule of the Hispanic monarchy. The institutions, government and legal traditions of each kingdom remained independent of each other; they merely had the same king of Habsburg Spain.  The alien laws (Leyes de extranjeria) determined that the national of one kingdom was a foreigner in all the other Iberian kingdoms.  The term Iberian union  was not used at the time, it is a creation of modern historians.