The 1495 syphilis epidemic at Naples

Charles VIII of France invaded Italy in September 1494 and reached Naples in February 1495 with an army of more than 30,000 mercenaries drawn from all over Europe. Among these troops a serious disease that no one had seen before was first documented. The French held Naples for a few months, then the army was demobilized, and the mercenaries went home or joined new wars, taking the infection with them.

It reached what are now Italy, France, Germany and Switzerland first, then Holland and Greece, then England and Scotland, and later Hungary and Russia. A military surgeon on the Naples campaign gave the first accurate description. The disease began with a painless ulcer on the penis and went on to high fever, a rash with itching, sores and pustules over the whole body, severe pain in the bones and joints, and nervous symptoms, sometimes killing within weeks or months. It was soon understood to be sexually transmitted. Each people blamed a neighbor: Italians, Germans and the English called it the French disease, and the French called it the Neapolitan disease.

An early name was lues, a common word for plague at the time. In 1530 the Italian poet and physician Girolamo Fracastoro published a poem about a shepherd called Syphilus, and his name became a synonym for the disease. In 1496 Albrecht Dürer, then 25, made a woodcut of a man with ulcerated skin to go with a poem by the physician Theodoric Ulsenius. Its inscription of 1484 refers to a planetary conjunction then read as an evil omen, and it is one of the earliest known images of the disease.

The origin is still argued. The oldest explanation holds that men returning from the West Indies with Columbus in March 1493 brought it to Europe, and skeletons with syphilitic changes have been found in the Americas but not in Europe from before his voyage. Others argue that a milder form already existed in the Old World and grew more aggressive in the wars and famines of the late 15th century. They point out that the gap between Columbus's return and early 1495 seems too short for an outbreak of that size, that at most a few dozen of his men served with Charles VIII, and that no one tied the voyage to the disease until around 1520.