Sir Robert Chesebrough, a chemist, was the one who invented Vaseline, also known as petroleum jelly.
He patented the product in 1872, but the product wasn't accepted until he travelled around New York doing demonstrations on himself.
He would burn his skin with acid or an open flame in front of an audience and then use the Vaseline to soothe the burn.
He passed out free samples to get the product into the public. He believed in his product so much that he claimed to even eat a spoonful every morning.