The House of Braganza was founded in 1442. This is when Afonso, 8th Count of Barcelos, was made Duke of Braganza. Alfonso (Alfonso I) was an illegitimate son of King João I of Portugal, of the House of Aviz. He was made a duke by his nephew, King Afonso V of Portugal. The feudal dukes quickly collected a fortune in properties, titles, and power. By the mid 1600s, the House was the most powerful in all of Portugal. It was also of the greatest houses of Iberia.