John Caius (born John Kays, October 6, 1510 - July 29, 1573) was an English physician. He was physician to Edward VI, Queen Mary and Queen Elizabeth. From this position he was dismissed in 1568 on account of his adherence to the Catholic Faith. He was incongruously accused both of atheism, and of keeping secretly a collection of ornaments and vestments for Catholic use. The latter were found and burned in the College court. He was elected nine times president of the College of Physicians. In 1564, he obtained a grant for Gonville and Caius College to take the bodies of two malefactors annually for dissection making him an important pioneer in advancing the science of anatomy. was also a pioneer naturalist, prepared to make his own observations about nature rather than simply relying on accepted authorities. He died in 1573 at the age of 82. His body was brought to Cambridge, and buried in the chapel under the monument which he had designed.