John Caius (born John Kays; 6 October 1510 – 29 July 1573), also known as Johannes Caius and Ioannes Caius, was an English physician, second founder of Gonville and Caius College, Cambridge, scholar, and physician to Edward VI and Mary I.
Early years
Caius was born in Norwich and was educated at Norwich School. 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, 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.
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.
Career
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.
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.
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 £624,676 in 2025). 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.
