Duke of Aveiro

The Dukedom of Aveiro was an aristocratic Portuguese title, granted in 1535 by King John III of Portugal to his 4th cousin, John of Lencastre, son of Infante George of Lencastre, a natural son of King John II of Portugal.

John of Lencastre was already Marquis of Torres Novas when the King granted him the new title of Duke of Aveiro. Later, their descendants strongly supported Philip II of Spain during the 1580 Portuguese succession crisis. Thus the Dukes became the second aristocratic House of Portugal, after the Braganzas.

Raimundo of Lencastre, 4th Duke of Aveiro maintained his House's traditional support for the Habsburg monarchy, even after the 1640 national revolution in Portugal. Therefore the Aveiro property was confiscated by the new Kings of the Braganza Dynasty, and granted in 1668 to his uncle, Peter of Lencastre, who already was Archbishop of Évora and general Inquisitor, becoming 5th Duke of Aveiro. He died in 1673 without issue.

The succession was given to his niece, Maria de Guadalupe of Lencastre, who was married to the Spanish Duke of Los Arcos. She returned to Portugal with her younger son, while her husband and her older son stayed in Spain. She regained the control of her House and estates and recognised the Braganzas royalty.

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