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John de Sequeyra

1712 – 1795

American physician

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About John de Sequeyra

Lived 1712 – 1795 (aged 82–83). John de Sequeyra was a physician.

John de Sequeyra ( – ) was a Portuguese-born American physician and writer. Born in Lisbon into a Portuguese Jewish family, he moved to the British colony of Virginia in 1745 and earned a living practising medicine. Sequeyra was the author of a group of writings on the various diseases in Virginia and the first visiting physician of the Hospital for the Maintenance of Idiots, Lunatics, and Persons of Insane or Disordered Minds in Williamsburg, Virginia.

Family and early life

João de Sequeira was born in Lisbon around 1712 into a New Christian family from Rio de Janeiro. His father was Francisco Machado de Sequeira (later Abraham de Sequeira Machado), a physician who was arrested in Rio de Janeiro in 1706 and taken to Lisbon two years later. His Inquisition's trial lasted until June 1709. Francisco Machado de Sequeira moved to London in the early 1730s, where he was circumcised and took a Jewish name, Abraham de Sequeira Machado. Sequeira Machado became a member of Bevis Marks Synagogue in London.

Medical career

Sequeyra studied medicine in the University of Leiden beginning in 1736 and received his degree in 1739 with a dissertation entitled "De Peripneumonia vera", which he dedicated to his older brother "Joseph Henry de Siqueyra, M.D., physician to the Portuguese in the East Indies and chief physicist to the Viceroy of Goa".

Tomatoes

John Hill once wrote – "Those who are us'd to eat with the Portuguese Jews know the value of it"; he was speaking of the tomato. John Custis IV, a Williamsburg resident, sent a letter to Peter Collinson, in 1741, inquiring about this thing called a "tomato". Tomatoes made their way to Colonial America by way of the West Indies Slave Trade – it was a staple food of the slaves who learned to discern the poisonous varieties from the edible varieties.

Thomas Jefferson himself informs us that introduction of the tomato as an edible fruit is due to the work of Dr. John de Sequeyra.

Works Three writings on medical matters written by Sequeira are known, which remained in manuscript until the 20th century. One is an annual report on the diseases in Virginia, published by Harold Gill in 1972. Six years later, Gill published another Sequeira's writing on the same subject, a king of a short summary of the annual reports. In 1997, Sarah McEntee wrote a BA thesis on Sequeyra and included the transcription of a third manuscript, a list of prevailing diseases in Virginia, including their description, symptoms and therapies.

Notes and references

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Important facts

Born
1712, Lisbon
Birth century
Died
1795
Occupation
Also known as
John de Sequerya

People in John de Sequeyra's life

Named in this biography and alive at the same time

Contemporaries

People whose lives overlapped John de Sequeyra's

Frequently asked questions

Who was John de Sequeyra?

American physician

When was John de Sequeyra born?

John de Sequeyra was born in 1712 in Lisbon.

When did John de Sequeyra die?

John de Sequeyra died in 1795.

What was John de Sequeyra's occupation?

John de Sequeyra was a physician.

Sources & further reading

· Wikipedia: John de Sequeyra

· Wikidata: Q16859286

· DBpedia: John de Sequeyra

Cite this page

APA: Biography.guide. (2026). John de Sequeyra. https://biography.guide/john-de-sequeyra/

MLA: "John de Sequeyra." Biography.guide, https://biography.guide/john-de-sequeyra/.

Chicago: "John de Sequeyra." Biography.guide. https://biography.guide/john-de-sequeyra/.

Data last updated: 2026-09-21 · Spot an error? Report a correction.

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