King Duarte I of Portugal, also known as Duarte I, reigned from 1433 to 1438. He was the son of King John I of Portugal and Philippa of Lancaster. Duarte was known for his efforts to promote peace and stability in Portugal during his short reign, as well as his interest in literature and the arts. Duarte's reign was marked by challenges, including conflicts with the Castilian Empire and internal political struggles. He was a patron of the Portuguese Renaissance and authored several works, including the "Livro da Ensinança de Bem Cavalgar" (Book on the Teaching of Good Horsemanship). His untimely death led to a succession crisis in the kingdom.