When his half-brother, King
Duarte I of Portugal, died in 1438, his son
Afonso V (Afonso's nephew) was an infant and the choice of regent was his sister-in-law, the Queen Mother
Eleonor of Aragon. This choice was not popular because Eleonor was Aragonese. Among the aristocracy, however — especially Afonso's inner circle —, Eleonor of Aragon was preferred. There were also doubts about Peter's political ability. At a meeting of the
Portuguese Cortes summoned by Afonso's half-brother
John, Lord of Reguengos de Monsaraz, the regency was awarded to the
Infante Peter, Duke of Coimbra, another half-brother of Afonso and an uncle of the young king. This choice pleased both the people and the fast-growing
bourgeoisie. In 1443, in a gesture of reconciliation, Peter made Afonso the first
Duke of Braganza. But, in 1445, Afonso took offence because
Isabella of Coimbra, Peter's daughter, became the choice for Afonso V's wife, and not one of his granddaughters. Indifferent to the intrigues, Peter continued his regency and the country prospered under his rule. It was during this period that the first subsidies for the exploration of the
Atlantic Ocean were appropriated under the supervision of
Henry the Navigator (another of Afonso's half-brothers). On 9 June 1448, King Afonso V came of age, and Peter turned over control of the country to the king. An ambitious man, Afonso persuaded his nephew, the young king, to turn against Peter. Influenced by Afonso, the king nullified all of Peter's edicts. The following year, under accusations that years later would prove false, Afonso V declared his uncle Peter a rebel. The situation became unsustainable and a civil war began. On 20 May 1449, during the
Battle of Alfarrobeira, near
Alverca, Peter was killed. After the Battle of Alfarrobeira, Afonso V gave new powers to his uncle Afonso and nine years later when he departed for
Africa, the regency was delegated to him. == Marriages and issue ==