Syphilis was a bit more severe and easier to catch in those days (i.e. kissing could spread it if you kissed a cheek with an open wound).
it was syphilis that initially caused the most widespread suffering and death. However, by the mid-sixteenth century, observers were beginning to note that it was declining sharply in virulence. As Frascatoro noted in 1546, ‘although this pestilential disease is at present still fully active, it is no longer the same as it was at first.’ Pustules, he reported, were ‘now only to be found on a very small number of patients, and the pains are negligible or very slight…The sickness is in decline.’ Either people had developed some resistance to the most extreme symptoms, or the disease itself had mutated into a less virulent form. Whatever the reason, by the 1540s it settled into the form, or forms it has more or less persisted in taking up to the present day.
The change in the way a disease acts is not unknown in history...In the last week, news reports say the HIV is getting less virulent in recent years too, and often diseases of history are hard to identify because they differed from the modern versions.
So anyway, the disease is mentioned in a lot of plays by Shakespeare, making some speculate that he might have had it. And he even might have been cured of it: Because back then they treated it with very hot baths
I never definitively state that Shakespeare had syphilis, rather that he may have received treatment for syphilis, and may have suffered untoward side effects. Gonorrhea and syphilis were not differentiated clinically until the eighteenth century, and the Elizabethans regarded them as a single disease entity. This is because co-infection with more than one type of venereal disease is a common phenomenon, then as now. If Shakespeare had only a less dangerous venereal disease, such as gonorrhea, he likely still would have underwent conventional therapy for syphilis, namely, "the powdering tub of infamy." The unfortunate "scalded chickens" and "boiled stuff" were immersed in hot baths, and exposed to mercury vapor, in the form of volatilized cinnabar. The toxicity of mercury is dose-dependent. The inorganic mercury once used to treat syphilis is not highly toxic in low doses, but modern experience has shown that the symptoms of mild mercury poisoning may become manifest as the nervous system ages.
I don't think Shakespeare died of syphilis, or that it affected his cognitive and creative abilities. The Elizabethan treatment for syphilis was probably surprisingly effective, for those that could afford it. Treponema pallidum lacks heat shock proteins, and is thus susceptible to thermal lysis. The German psychiatrist Julius Wagner-Jauregg won the Nobel Prize for Medicine in 1927 for his use of deliberate malaria infection as a treatment for neurosyphilis. (The high fevers provoked by malaria killed off the spirochetes, but killed about 9% of patients.) Dissatisfaction with the toxicity of malaria therapy and arsenic therapy led to the revival of the Elizabethan hot bath treatment in the 1940s, just prior to the phenomenal success of penicillin.
a journal article from JMVH has more on treatment in the good old days:
the hot baths were part of the treatment with mercury, and ironically maybe the very hot bath was more efficient...
Beck (1997) describes a typical mercury treatment :
“A patient undergoing the treatment was secluded in a hot, stuffy room, and rubbed vigorously with the mercury ointment several times a day. The massaging was done near a hot fire, which the sufferer was then left next to in order to sweat. This process went on for a week to a month or more, and would later be repeated if the disease persisted. Other toxic substances, such as vitriol and arsenic, were also employed, but their curative effects were equally in doubt.” 
Mercury had terrible side effects causing neuropathies, kidney failure, and severe mouth ulcers and loss of teeth, and many patients died of mercurial poisoning rather than from the disease itself. Treatment would typically go on for years and gave rise to the saying,
“A night with Venus, and a lifetime with mercury” 
Herbs were also used, but not felt to be as successful.
all of which makes one wonder about "sweat baths" popularity in some AmerIndian traditions.
In Minnesota, it was a way to clean oneself and get some relief from arthritis and other ills, especially in the 8 months of cold weather, similar to the saunas of the Scandanavians or the Turkish baths.
NewWorldEncyclopedia article HERE.
I am impressed that when they noted the deaths of some white folks in a newage type sweat, they didn't get a pseudo Indian to comment, but asked Arvol LookingHorse of the Sioux, who is a true medicine man.
a discussion of the traditional Mexican sweat bath is found here.
a description of the sweat lodge of North American tribes can be found here.
As for baths: Yes, medieval people did take baths.
sometime they only did a "full body bath" twice a year, but they washed in between. Many dark age and medieval tales discuss the lady of the house getting a bath ready for the visiting knights.
Cracked has a list of myths about the middle ages...
...not only was it common for medieval folk to wash their hands before and after eating, it was also customary to offer to bathe with guests when they entered your home, something The Man has repeatedly reminded us is no longer acceptable in modern society. Medieval demand for soap (usually made from animal fats, with a variety of oils and salts added) was so great that by the 13th century, soap was being made on an almost industrial scale in Britain, Italy, Spain, and France.
So why do we picture everyone as wallowing in their own filth back then? Well, things changed all at once. If only an act of God could change Europe's epic bathing culture, they got one -- in the mid-14th century, the Black Death strolled up and kicked Europe right in the teeth with its pestilence boot. Suddenly, smart people were telling the previously washed masses that bathing was a surefire way to open your body's pores and invite in all the bad spirits or gremlins or whatever (they weren't too savvy on what caused illness back then).