Origin
For many years, syphilis was thought to have originated from the "New World" (the Americas). This theory was supported by historical records stating that the disease was brought back by Columbus during his trans-Atlantic journeys in the 15th and 16th centuries. Evidence both supporting this theory in the Americas and failing to support evidence of the disease in the "Old World" made the idea easy to accept. Many skeletal remains were found in the New World dating back to over 3000 B.C.E. However, recent evidence supports another theory that the disease existed in other parts of the world prior to Columbus sailing across the seas. Since these findings, researchers have debated whether syphilis originated from a "Pre-Columbian" Old World or a "Post-Columbian" New World.
One of the reasons that syphilis, along with the other Treponematites, is so hard to find in pre-Columbian populations is because they mimic other conditions such as Osteomyelitis, Tuberculosis, and Leprosy. Postmortem damage such as water, tree roots, insects, and the weight of soil also make lesions on pre-Columbian specimens sometimes hard to distinguish. Many supporters of this argument suggest that syphilis may have been confused with leprosy in the medieval period due to their similar ulcerations, destruction of the nose, and lower extremity abnormalities. To counter this theory, many non-believers argue that there might have been a mild, endemic form of treponematosis in the Old World but certainly not any of the aggressive forms that we see today. The pre-Columbian evidence of these diseases are sporadic and limited to Europe, although other possible cases have been reported in Asia, the Middle East, and other regions. Archaeologists agree that there is now too much evidence to say definitively that syphilis originated in the New World.
The widely-accepted theory is the idea that Columbus and his crew brought back the venereal form of syphilis from the Caribbean and America. Evidence of treponematosis is very abundant in ancient populations of the Americas and barely evident in other populations of the Old World from this time. Outbreaks of the disease in 15th and 16th century Europe support the theory that the disease did not exist prior to Columbus' journey. The first recorded outbreak spread rapidly through Naples, Italy in 1494. Since its arrival in Europe, many have pointed the blame to other European populations as being the cause of the illness. "The Great Pox" was the common name in the 16th century, but when an outbreak of the disease spread through the French Army it became the "French Disease". It was also called the "Spanish Disease" by the Italians, the French called it the "English Disease" and the "Italian Disease", the Russians called it the "Polish Disease", and the Arabs called it the "Disease of the Christians". As you can see, there was as much interest back then as there is today to figure out the origin of this dreadful disease.