Duarte of Portugal (Edward, in English), the Philosopher or the Eloquent, the 11th king of Portugal, was born in Viseu on October 31 1391 and he died in Tomar on September 13 1438. He was the son of King João I of Portugal (John I of Portugal) and his wife, Philippa of Lancaster, a daughter of John of Gaunt.

As a prince, Edward (Duarte) always followed his father, King João I, in the affairs of the kingdom. He was knighted in 1415, after the Portuguese captured the city of Ceuta in North Africa, across from Gibraltar. He became king in 1433 when his father died of the plague and he soon showed interest in internal consensus. During his short reign of five years, Duarte called the Cortes (the national assembly) no less than five times to discuss internal affairs and politics. He also followed the politics of his father concerning the maritime exploration of Africa. He encouraged and financed his famous brother, Prince Henry the Navigator who founded a school of maritime navigation at Sagres and who initiated many expeditions. Among these, that of Gil Eanes in 1434 first rounded Cape Bojador on the NW coast of Africa, leading the way for further exploration southward along the African coast.

The colony at Ceuta rapidly became a drain on the Portuguese treasury and it was realised that without the city of Tangier, possession of Ceuta was worthless. When Ceuta was lost to the Portuguese, the camel caravans that were part of the overland trade routes began to use Tangier as their destination. This deprived Ceuta of the materials and goods that made it an attractive market and a vibrant trading locale, and it became an isolated community.

In 1437, his brothers, Henry (Henrique) and Fernando, persuaded Duarte to launch an attack on Morocco in order to get a better African base for future Atlantic exploration. The expedition was not unanimously supported: Pedro, Duke of Coimbra and John, duke of Aveiro were both against the initiative; they preferred to avoid conflict with the king of Morocco. They proved to be right. The resulting attack on Tangier was successful, but at a great cost of men. Duarte's youngest brother, Fernando, was captured, kept as a hostage, and he died later in captivity in Fez. Duarte died soon after the Tangier attack of the plague, like his father and mother (and her mother) before him.

Another less political side of Duarte's personality is related to culture. A reflective and scholarly prince, he wrote the treatise O Leal Conselheiro (The Loyal Counsellor) as well as other books on hunting and several poems. He was in the process of revising the Portuguese law code when he died.

Duarte's marriages and descendants

• By his wife, princess Eleanor of Aragon (1402-1455), a daughter of Ferdinand I of Aragon and Leonor Urraca de Castilla
  • John (1429)
  • Philippa (1430-1439)
  • Afonso V, king of Portugal (1432-1481)
  • Mary (1432)
  • Ferdinand of Portugal, Duke of Viseu (1433-1470), father of Manuel I, king of Portugal
  • Eleanor, princess of Portugal (1434-1467), married Frederick III, Holy Roman Emperor
  • Edward (1435)
  • Catherine (1436-1463)
  • Joan, princess of Portugal (1439-1475), married king Henry IV of Castile

See also: Kings of Portugal family tree