Medical research in the twentieth century mostly takes place in the lab; in the Renaissance, though, researchers went first and foremost to the library to see what the ancients had said.
Perhaps more than any other disease before or since, syphilis in early modern Europe provoked the kind of widespread moral panic that AIDS revived when it struck America in the 1980s.
Shortly after Christopher Columbus and his sailors returned from their voyage to the New World, a horrifying new disease began to make its way around the Old. The "pox," as it was often called, erupted with dramatic severity.
Was this an old disease, and, if so, which one? If it was new, what did that say about the state of medical knowledge? And in any case, how could physicians make sense of it?
Even more than this, however, the sick - like lepers - were often reviled because people believed that they had brought their torments upon themselves.
Often, city fathers blamed prostitutes for the disease, and some threatened to brand their cheeks with hot iron if they did not desist from their vices.