John Caius
Born	John Kays 6 October 1510 Norwich, England
Died	29 July 1573(1573-07-29) (aged 62) London, England
Nationality	English
Alma mater	Gonville Hall, Cambridge University of Padua
Known for	Second founder of Gonville and Caius College, Cambridge
Scientific career
Fields	Medicine
Institutions	Gonville and Caius College, Cambridge
Academic advisors	Montanus Vesalius

John Caius (born John Kays /ˈkiːz/;^[a] 6 October 1510 – 29 July 1573), also known as Johannes Caius and Ioannes Caius, was an English physician, and second founder of Gonville and Caius College, Cambridge. Scholar and physician to Edward VI and Mary I of England.

Caius was born in Norwich and was educated at Norwich School.^[1] In 1529, he was admitted as a student at Gonville Hall, Cambridge, founded by Edmund Gonville in 1348, where he seems to have mainly studied divinity.

After graduating in 1533,^[2] he visited Italy, where he studied under Montanus and Vesalius at Padua. In 1541 he took his degree as a physician at the University of Padua.^[3]

In 1543 he visited several parts of Italy, Germany and France and then returned to England. Upon his return from Italy he Latinised his surname which was somewhat fashionable at the time.

Caius was a physician in London in 1547, and was admitted as a fellow of the College of Physicians, of which he was for many years president.^[3]

In 1551 he was attending in Shrewsbury when a notable outbreak of sweating sickness occurred in the town; the following year, after his return to London, he published A Boke or Counseill Against the Disease Commonly Called the Sweate, or Sweatyng Sicknesse (1552), which became the main source of knowledge of this disease, now understood to be influenza.^[4]

In 1557 Caius, at that time physician to Queen Mary, enlarged the foundation of his old college, changed the name from "Gonville Hall" to "Gonville and Caius College", and endowed it with several considerable estates, adding an entire new court at the expense of £1,834 (equivalent to £681,230 in 2023). He accepted the mastership of the college 24 January 1559 on the death of Thomas Bacon, and held it until about a month before his own death.^[3]

He was physician to Edward VI, Queen Mary and Queen Elizabeth.^[3] From this position he was dismissed in 1568 on account of his adherence to the Roman Catholic faith. He was incongruously accused both of atheism, and of keeping secretly a collection of ornaments and vestments for Roman Catholic use. The latter were found and burned in the college court.^{[citation needed]}

He was elected nine times president of the College of Physicians, an account of which, Annales collegii medicorum 1520-1565, he left in manuscript.

He returned to Cambridge from London for a few days in June 1573, about a month before his death, and resigned the mastership to Thomas Legge, a tutor at Jesus College. He died at his London house, in St Bartholomew's Hospital, on 29 July 1573, but his body was brought to Cambridge, and buried in the chapel under the monument which he had designed.^[3]

The question of whether he was the inspiration for the character of Dr Caius in Shakespeare's play the Merry Wives of Windsor has been discussed at length by Arnold McNair, 1st Baron McNair.^[5]

Caius was a learned, active and benevolent man. In 1557 he erected a monument in St Paul's Cathedral to the memory of Thomas Linacre. In 1564, he obtained a grant for Gonville and Caius College to take the bodies of two malefactors annually for dissection; he was thus an important pioneer in advancing the science of anatomy. He probably devised, and certainly presented, the silver caduceus now in the possession of Caius College as part of its insignia. He first gave it to the College of Physicians, and afterwards presented the London College with another.^[3]

Caius was also a pioneer naturalist, prepared to make his own observations about nature rather than simply relying on accepted authorities. He was ready to make journeys about the country to see and record unusual animals. As such he could be considered also a pioneer of zoology, not yet recognised as a separate science.

He corresponded with the Swiss naturalist Conrad Gesner, with whom he had made friends while returning from Padua. He wrote a study of British dogs to send to Gesner as a contribution (not used) to Gesner's Historiae animalium, and also sent Gesner drawings of dogs, which were printed in later editions of Gesner's work.^[6] Caius' Catholic religious convictions did not prevent his friendship with the Protestant Gesner (indeed, the Historiae Animalium, to which Caius contributed, was under Pope Paul IV placed on the Roman Catholic Church's list of prohibited books).^[7]

His last literary production was a history of Cambridge University, Historia Cantabrigiensis Academiae (London, 1574).

• Annals of the College from 1555 to 1572
• Translation of several of Galen's works, printed at different times abroad.
• Hippocrates de Medicamentis, first discovered and published by Dr Caius; also De Ratsone Vicius (Lov. 1556, 8vo)
• De Mendeti Methodo (Basel, 1554; London, 1556, Svo)
  • Reprint: Caius, John (1912) [1556]. Roberts, E. S. (ed.). De Mendendi Methodo (in Latin). Vol. Liber I, II. Cambridge: University Press. pp. 1–56. Retrieved 7 September 2020.
• A Boke or Counseill against the Disease Called the Sweate, London 1552
  • Reprint: Caius, John (1912) [1552]. Roberts, E. S. (ed.). A Boke or Counseill against the Disease Called the Sweate or Sweatyng Sicknesse. Cambridge: University Press. pp. 1–36. Retrieved 7 September 2020.
  • Reprint: Caius, John, A Boke or Counseill against the Disease Called the Sweate, London 1552. Facsimile ed., 1937, Scholars' Facsimiles & Reprints, ISBN 978-0-8201-1182-7.
• De Ephemera Britannica (Account of the Sweating Sickness in England) (London, 1556, 1721)
  • Reprint: Caius, John (1912) [1554]. Roberts, E. S. (ed.). De Ephemera Britannica (in Latin). Vol. Liber unus. Cambridge: University Press. pp. 57–115. Retrieved 7 September 2020.
• History of the University of Cambridge (London, 1568, 8vo; 1574, 4to, in Latin)
  • Reprint: Caius, John (1912) [1574]. Roberts, E. S. (ed.). Historiae Cantebrigiensis Academie (in Latin). Vol. Liber I, II. Cambridge: University Press. pp. 1–116. Retrieved 7 September 2020.
• De Thermis Britannicis; but it is doubtful whether this work was ever printed
• De Rariorum animalium atque stirpium historia, libellus.(Of Some Rare Plants and Animals) (London, 1570)
  • Reprint: Caius, John (1912) [1570]. Roberts, E. S. (ed.). De Rariorum animalium atque stirpium historia, Liber unus (in Latin). Cambridge: University Press. pp. 23–65. Retrieved 7 September 2020.
    • Digital text: De Rariorum Animalium atque Stirpium Historia at Project Gutenberg
• De Canibus Britannicis (1570, 1729)
  • Reprint: Caius, John (1912) [1570]. Roberts, E. S. (ed.). De Canibus Britannicis (in Latin). Cambridge: University Press. pp. 1–19. Retrieved 7 September 2020.
  • Of Englishe Dogges: The Diuersities, the Names, the Natures, and the Properties (London, 1576).
  • Reprint: Caius, John (1912) [1576]. Roberts, E. S. (ed.). Of Englishe Dogges: The Diuersities, the Names, the Natures, and the Properties. Translated by Fleming, Abraham. Cambridge: University Press. pp. 1–47. Retrieved 7 September 2020.
• De Libris suis: De Libris propriis (London, 1570).
  • Reprint: Caius, John (1912) [1570]. Roberts, E. S. (ed.). De Libris suis (in Latin). Vol. 1. Cambridge: University Press. pp. 67–111. Retrieved 7 September 2020.
• De Pronunciatione Graecae et Latinae Linguae (London, 1574)
  • Reprint: Caius, John (1912) [1574]. Roberts, E. S. (ed.). De Pronunciatione Graecae et Latinae Linguae cum scriptione nova libellus (in Latin). Cambridge: University Press. pp. 1–19. Retrieved 7 September 2020.
    • Digital text: De Pronunciatione Graecae & Latinae Linguae at Project Gutenberg

• Thomas Caius, Master of University College, Oxford (1561–1572)
• Bloodhound

• Venn, John (1897). Biographical History of Gonville and Caius College. Cambridge: University Press.
• Nutton, V (1985). "John Caius and the Eton Galen: medical philology in the Renaissance". Medizinhistorisches Journal. 20 (3): 227–52. PMID 11616032.
• Nutton, V (October 1979). "John Caius and the Linacre tradition". Medical History. 23 (4): 373–91. doi:10.1017/s0025727300052030. PMC 1082578. PMID 390265.
• Cooke, A M (July 1973). "Dr John Caius, 1510-1573". Journal of the Royal College of Physicians of London. 7 (4): 365–71. PMC 5368824. PMID 4577633.
• Alberti, F (October 1961). "Anatomy in London. Anatomic teaching in London and John Caius, student of the Padua School before Harvey". Minerva Med. (in Italian). 52: Varia 1893–6. PMID 13860128.
• O'Malley, C D (April 1955). "The relations of John Caius with Andreas Vesalius and some incidental remarks on the Giunta Galen and on Thomas Geminus". Journal of the History of Medicine and Allied Sciences. 10 (2): 147–72. doi:10.1093/jhmas/X.2.147. PMID 14367793.
• Wohlfarth, P (December 1954). "[John Caius and his time.]". Deutsches Medizinisches Journal (in German). 5 (23–24): 689–93. PMID 14352903.

• John Caius on the Gonville and Caius College website
• Works by John Caius at Project Gutenberg
• Works by or about John Caius at the Internet Archive
• Works by John Caius at LibriVox (public domain audiobooks)
• Caius, John; Venn, John (1912). Roberts, E. S. (ed.). The works of John Caius, M.D., second founder of Gonville and Caius College and master of the college, 1559-1573. Cambridge: University Press. Retrieved 7 September 2020. (this anthology lacks global pagination)