Ninth King of Portugal (1367-1383) born in Lisbon, whose reign was marked by the economic growth of Portugal and by wars with the neighboring kingdom of Castile, whose throne he disputed. Dedicated to wars, even with the support of England, he suffered successive defeats and was compelled to sign a peace treaty (1382) with the Castilians. He was the son of King Pedro I of Portugal and Princess Constance of Castile and succeeded his father (1367) and when Pedro I of Castile the Cruel or the Punisher (1350-1369) died without direct heirs (1369), claimed rights to the Castilian throne as great-grandson of Sancho IV. The pretensions of other alleged heirs, such as the Dukes of Lencastre and Henrique da Trastamara, led to three exhausting wars and several agreements, particularly involving marriages.
Alongside this disastrous foreign policy, he internally enacted laws that encouraged the progress of agriculture, foreign trade, merchant marine, and the army. He implemented the historic sesmarias law, which ended unproductive property, making mandatory the cultivation of abandoned land under penalty of being divided up, fostered Portuguese farming and the production of foods. He married national scandal with his romance with Leonor Teles de Menezes, of dubious morals and the wife of one of his courtiers, whom he married after her marriage was annulled.
After her death in Lisbon, his widow was appointed regent in the name of her daughter with the dead king, Beatriz de Portugal, betrothed to King João I of Castile, as an agreement to end the war with Castile (1382). Taking advantage of the Portuguese's desire for independence, João, Mestre de Aviz and bastard brother of Fernando, declared himself king of Portugal and after two years of political and social chaos (1383-1385), João became the first king of the Aviz Dynasty (1385). as D. John I.
Source: http://www.dec.ufcg.edu.br/biografias/
Order F - Biography - Brazil School
Source: Brazil School - https://brasilescola.uol.com.br/biografia/fernando-i-portugal.htm
