John I (Portuguese: João [ʒuˈɐ̃w̃]; 11 April 1357 – 14 August 1433), also called John of Aviz, was King of Portugal from 1385 until his death in 1433. He is recognized chiefly for his role in Portugal's victory in a succession war with Castile, preserving his country's independence and establishing the Aviz (or Joanine) dynasty on the Portuguese throne. His long reign of 48 years, the most extensive of all Portuguese monarchs, saw the beginning of Portugal's overseas expansion. John's well-remembered reign in his country earned him the epithet of Fond Memory (de Boa Memória).
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Early life
John was born in Lisbon as the natural son of King Peter I of Portugal by a woman named Teresa, who, according to the royal chronicler Fernão Lopes in the Chronicle of the King D. Pedro I, was a noble Galician. In the 18th century, António Caetano de Sousa found a 16th-century document in the archives of the Torre do Tombo in which she was named as Teresa Lourenço.
John was raised and educated by Nuno Freire de Andrade, a Galician Grand Master of the Order of Christ. In January 1364, at Chamusca, Nuno presented John to Peter I for the first time and secured John's appointment as Grand Master of the Order of Aviz.
When John's half-brother Ferdinand I died in October 1383 without a male heir, strenuous efforts were made to secure the succession for Beatrice, Ferdinand's only daughter and heir presumptive. Beatrice had married King John I of Castile, but popular sentiment was against an arrangement in which Portugal would have been virtually annexed by Castile. The 1383–1385 Portuguese interregnum followed, a period of political anarchy, when no monarch ruled the country.




