Duarte Fernandes (16th century) was a Portuguese diplomat, explorer, and was the first European to establish diplomatic relations with Thailand, when in 1511 he led a diplomatic mission to Ayutthaya Kingdom (Kingdom of Siam), after the Portuguese conquest of Malacca.
Duarte Fernandes was a Portuguese tailor who traveled to Malacca as part of the first expedition of Diogo Lopes de Sequeira in September 1509. When sailors grew anxious that the expedition was delaying a return to Portugal, a number of sailors attempted to force de Sequeira to order the ships home. In the sequence of a failed plot to destroy the expedition, Fernandes was among nineteen Portuguese that stood arrested in Malacca. His amicable nature spared him the fate of the other conspirators. Together with Rui de Araújo, Fernandes gathered knowledge about the culture of the region and became a de facto envoy of Afonso de Albuquerque.
In 1511 the Portuguese conquered Malacca. Knowing of Siamese ambitions over Malay, Albuquerque sent Fernandes in a diplomatic mission to the court of the King of Siam, Ramathibodi II. Fernandes was dispatched and became the first European to arrive in Siam, where he was successful in establishing amicable relations between the Kingdom of Portugal and the Kingdom of Siam, returning with a Siamese envoy bearing gifts and letters to Albuquerque and the king of Portugal. Five years after that initial contact, Ayutthaya and Portugal concluded a treaty granting the Portuguese permission to trade in the kingdom.
Fernandes became one of the first Europeans to take an interest in Chinese shipbuilding, as he traveled in a Chinese junk on his return journey to Malacca and, being a former tailor, was fascinated by the junk's sails.
- Manuel Teixeira, The Portuguese missions in Malacca and Singapore (1511-1958), Agência Geral do Ultramar, 1963 pp. 38, 54
- Asian review, Volume 13 by Čhulālongkō̜nmahāwitthayālai. Sathāban ʻĒchīasưksā, p.39
- Chakrabongse, C., 1960, Lords of Life, London: Alvin Redman Limited
- Donald Frederick Lach, Edwin J. Van Kley, "Asia in the making of Europe", pp. 520-521, University of Chicago Press, 1994, ISBN 978-0-226-46731-3