A 16th-century portrait of King Edward IV of England                 

Syphilis is a venereal disease that usually develops slowly in adults, taking years or decades to emerge. However, the symptoms of the disease, including large chancres in the mouth or genital areas, and later on fatal damage to the brain and nervous systems, made syphilis a much-feared ailment in early modern Europe.

In her book, Medieval Syphilis and Treponemal Disease, Marylynn Salmon devotes a chapter to the death of King Edward IV and notes that he would have been a prime candidate to be infected by syphilis. While most medieval Europeans were exposed to forms of treponematosis as children – through playing together and sharing cups – their version was largely benign and would have protected them as adults from the more damaging syphilis. However, Edward came from an elite family where he had less exposure to other children and better hygiene. Therefore, he would have been susceptible as an adult to the venereal form of the disease.

Because syphilis often resembles other diseases, including leprosy, Edward and his physicians may not have even that the king suffered from this. However, two contemporary writers with insider access to Edward’s court offer some intriguing clues. The first is the Crowland Chronicle, which was probably written by a member of Edward’s royal council. The author seems to give a confusing answer to why the king died:

Salmon believes that the odd choice of words – that the disease was unknown yet was well enough known that it would be hard to cure in a person of lesser status – is very revealing. "The comment makes little sense unless we consider the possibility that Edward suffered from treponematosis, a disease unusual for having different outcomes in its endemic and venereal forms. Apparently, the chronicler was familiar enough with the disease to understand this, indicating that it was common in fifteenth-century England."

The second source about Edward’s death that Salmon finds interesting comes from Domenico Mancini, an Italian monk visiting England. Mancini wrote a report on what was happening in the English court for one of the counsellors of the King of France and was able to learn information from Edward’s courtiers. In his report, he states the English king had become depressed over a failed attempt to usurp the Scottish throne:

The idea that Edward died because of a fishing trip would have been farfetched even in the fifteenth century, which leads one to question why Mancini wrote this paragraph. Salmon believes that when the report says the King went "fishing" it really means ‘having sex’. There is a lot of evidence from the later Middle Ages that shows fish and fishing as a symbol for sexuality – examples of this would include the use of the codpiece and depictions of mermaids. Therefore Mancini was trying to be very cryptic in suggesting that the English king’s well-known sexual proclivities had led him to fall victim to the deadly disease.

According to Salmon, King Edward IV’s death was part of a more widespread problem afflicting elites in late medieval Europe. Syphilis was, in the words of one sixteenth-century physician, "the disease of the magnates." There was much fear about this disease in various royal courts as well as in the Papal Curia, but one with that had "a certain degree of obfuscation in the medical literature, as kings and noblemen sought to prevent their social inferiors, contemporaries, and posterity from learning about the more terrible scourge that God had sent to punish them for their sins."