During the thirteenth century universities were founded in some twenty important cities in Europe, and in connection with most of them a medical school was established. These educational institutions were the result of the initiative of ecclesiastics; their officials all belonged to the clerical body, most of their students were considered as clerics–and indeed this was the one way to secure them against the calls for military service which would otherwise have disturbed the enthusiasm for study–and the Popes were considered the supreme authority over all the universities. In spite of this thoroughly ecclesiastical character of the universities and educational institutions, there is not a hint of interference with the teaching of medical science and abundant evidence of its encouragement. Indeed, for anyone who knows the story of the universities of the thirteenth century, it is practically impossible to understand how there could have arisen any tradition of ecclesiastical opposition to education in any form, and there is not a trace of foundation for the stories with regard to ecclesiastical intolerance of science, which are supposed to be supported by certain Papal decrees.
The best possible demonstration of the maintenance of the most amicable relations between churchmen and physicians during the century in which these decrees were issued is also the most interesting fact in the history of medicine during the thirteenth century. It is not generally known that one of the most distinguished physicians of the thirteenth century, one who wrote a book on the special subject of eye diseases that is still a classic, afterwards became Pope under the name of John. He is variously known as John XIX., John XX., or John XXI., according as certain occupants of the Papal throne are considered to be of authority or not. He was educated at Paris, and probably spent some time at Montpelier. Under the name of Peter of Spain, though he was what we should now call a Portuguese, he subsequently taught physic at the University of Sienna. Here he wrote the famous little work on the Diseases of the Eye, which was reviewed by Dr. Petella, physician-in-chief of the Royal Italian Marine, in Janus, the International Archives for the History of Medicine and for Medical Geography in 1898. Petella does not hesitate to proclaim him one of the greatest men of his time. Daunou, one of the continuators of the Benedictines’ literary history of France, says that this Peter of Spain was one of the most notable persons in Europe in his generation.
James J. Walsh, The Popes and Science (1908)