Manuel I of Portugal
Manuel's mother was the granddaughter of King John I of Portugal, whereas his father was the second surviving son of King Edward of Portugal and the younger brother of King Afonso V of Portugal. In 1495, Manuel succeeded his first cousin, King John II of Portugal, who was also his brother-in-law, as husband to Manuel's sister, Eleanor of Viseu.
John I of Castile
King Ferdinand I of Portugal had died on 22 October 1383. His widow, Leonor Telles de Menezes, under the Treaty of Salvaterra de Magos and by the previous testament of the deceased king, declared herself Regent in the name of her daughter and son-in-law. From then onwards, Leonor ruled with her lover, João Fernandes Andeiro, second Count of Ourém, also called "Conde Andeiro", a Galician who had been Fernando's chancellor, which angered the nobility and the lower classes. The news of the death of Ferdinand came to John I and Beatrice in Torrijos, with the closing of the court in Segovia. The Master of Aviz wrote John, urging him to seize the Portuguese crown by right of his wife, and the Master himself would assume the regency. To avoid problems with John the Infante of Portugal, the dynastic eldest son of Inês de Castro, John I had him and his brother Dinís imprisoned in the Alcazar of Toledo. King John I then met the Council in Montalbán and sent Alfonso Lopez de Tejada with instructions for the regent, now Queen Mother, to proclaim Beatrice and himself the rulers of Portugal. The proclamation was announced, first in Lisbon, Santarém and other important places, and then, some days after the assassination of Count Andeiro, in all the country. Yet in Lisbon and elsewhere, as in Elvas and Santarém, popular sentiment favoured John the Infante.
John I of Castile assumed the title and coat of arms of King of Portugal, which investiture was recognized by the Pope of Avignon, and ordered the deployment of his troops when the Bishop of Guarda and chancellor to Beatrice, Afonso Correia, promised to deliver the support of the people. He then entered the country with his wife to ensure the obedience of the Portuguese people to him as King by the right of his wife, although they considered him merely a pretender.