Phineas Taylor (P.T.) Barnum - born on this day in 1810 tiny Bethel, Connecticut - was a showman, businessman and politician. In the 18th Century he was primarily famous for his entertainment career, focusing on putting on travelling shows featuring music and theater. However, he also used the platform to promote hoaxes and "curiosities" such as General Tom Thumb, a child with dwarfism who Barnum adopted - some would say "exploited" - and toured with, bringing in massive crowds and profits.
In skepticism Barnum is probably most associated with the eponymous "Barnum Effect" (covered in an earlier fact) where subjects seem to agree that often incredibly vague statements are written with themselves in mind. Alongside this it is claimed (although not true) that Barnum was the originator of the phrase "There's a sucker born every minute". This phrase will ring alarm bells with some skeptics and go some way to explaining why many of us get involved with it. Where Barnum toured curiosities some people sell dangerous substances as medicine.
Outside of entertainment Barnum was also a politician, serving in the state legislature as a Republican. He, ironically, spoke in favour of ratifying the constitutional amendment on slavery and supported the right of black citizens to have an equal vote. He also was a noted philanthropist, instrumental in the founding of a non-profit hospital in the city of Bridgeport, CT - although his philosophy on philanthropy was that it should be "profitable" down the line, like an investment.