Eleventh king of Portugal, son of King John I and D. Filipa of Lancaster, is born in Viseu on October 31st, 1391. He reigned for five years - a short but outstanding period. He strongly drove the course of internal politics and maritime expansion, namely through his campaigns in Northern Africa.

In terms of national policy he issued the Mental Law - inspired in the legal set that his father had in mind for the kingdom´s reform which was left unfinished due to the monarch´s passing. During his reign he summoned the assembly courts five times (Santarém, 1433 and 1434, Évora, 1435 and 1436 and Leiria, 1438), in a constant effort to hear his subjects concerns.

King Duarte´s reign was marked by the successful passing of the Bojador Cape by Gil Eanes - this allowed for a quicker exploration of the African coastline and sped up the maritime exploration. With the support of Queen D. Leonor and her brothers, D. Fernando and D. Henrique, he begins his policies of conquering lands in Northern Africa even though he was opposed by his own brothers. The military disaster of Tangiers, resulting in the death of D. Fernando, marked King Duarte and his family in dramatic fashion.

Duarte was a man interested in culture and knowledge. He wrote a number of poetry and prose books - the highlights are Leal Conselheiro (Loyal Counsellor) and the Livro da Ensinança de Bem Cavalgar Toda Sela (The Learning Book of Riding Successfully All Saddles)

He passed away in Tomar - victim of the plague - at the Court of the Convent of Christ on September 13th, 1438 and was buried in the Avis Dynasty Pantheon at the Batalha Monastery.