Why is the doctor in the Merry Wives of Windsor called Caius?

JOHN CAIUS, born in 1510, was, from 1559 to 1573,1 Master of Gonville and Caius College, which he refounded and re-endowed. His father resided in Norwich but was of Yorkshire origin, and the name is probably Keys or Kees, though it occurs in the college records in ten different spellings: Kees, Keys, Keis, Kesse, Cais, Kaius, Keyse, Cayus, Keysse, Caius. Persons bearing the name of Kayes, Keyes, Kays or Keys, were common, but very few of them moved in the circles in which it was customary to latinize one's name. The D.N.B. records a John Caius who flourished about 1480 and translated a Latin poem into English, and a Thomas Caius or Key, a fellow of All Souls and Master of University College, Oxford, who crossed swords with our John Caius of Cambridge on the relative antiquity of the two universities and died in 1592. Neither of these candidates for representation in The Merry Wives can be regarded as 'starters'. In 1539 John Caius of Cambridge left England for the purpose of studying medicine in the University of Padua where he graduated M.D., spending five years in Italy, and became a professor. He returned to England in 1545 after making many important medical contacts and examining many manuscripts of Galen and Hippocrates, some of which he was able to bring to England.' He then developed a leading practice as a physician, became President of the College of Physicians nine times and was appointed physician to Edward VI, Mary and (until 1568) Elizabeth. He died in 1573. It is clear that he was one of the most eminent medical practitioners and scholars in England.3 Unless the name in the play was a pure fabrication by Shakespeare, which is almost impossible, it was probably adopted in the hope or belief that it would have a medical association. History does not record any obvious contemporary of Dr. Caius whose position and personality could have suggested the name, but that does not excuse us from investigating its possible sources or explanations. As we shall see later, the presence of a comic foreign doctor in The Merry Wives can cause no surprise, but the complete incongruity of the Dr. Caius of the play with Dr. Caius of Cambridge calls for some examination of the play and the choice of the name.