The earliest documented clowns date all the way back to 2400 BCE in ancient Egypt. Clowns appeared in ancient Greek and Roman societies, eventually evolving into court jesters in the late Middle Ages. These professionals would openly mock sex, food, drink, and the monarchy, all the while behaving maniacally for a laugh.
Source: Smithsonian Magazine
London entertainer Joseph Grimaldi was said to have invented the modern clown in the early 1800s. Grimaldi performed physical comedy while wearing white face paint with red patches on his cheeks and bizarre colorful costumes. He was known for being extremely depressed outside his routine: His first wife died during childbirth, his father was tyrannical, and his son became an alcoholic clown who drank himself to death at age 31.
Source: Smithsonian Magazine
Around the same time in France, everyone was laughing at Jean-Gaspard Deburau's Pierrot, a clown character with a white face, black eyebrows and red lips — one of the first professional silent mimes. He was universally beloved in France, but in 1836 Deburau killed a boy with a blow from his cane after the boy taunted him. Though he was ultimately acquitted, the image of a killer clown stuck in the public conscious.
Source: Smithsonian Magazine
In 1892, an Italian Opera called "Pagliacci" ("clowns") became extremely popular with the public. The main character was Canio, a cuckolded clown who murdered his cheating wife on stage during the final act. It's still a widely-staged play to this day.
Source: Smithsonian Magazine
Clowns became an integral part of big-top circuses, acting as comic relief to the death-defying circus stunts. At the circus, humor, horror, and death were all intertwined. French literary critic Edmond de Congourt said in 1876 that "the clown's art is now rather terrifying and full of anxiety and apprehension, their suicidal feats, their monstrous gesticulations and frenzied mimicry reminding one of the courtyard of a lunatic asylum.”
Source: Smithsonian Magazine
By the late 19th century, clowns and circus acts had blossomed in America. Three-ring circuses traveled around the US on trains and "hobo" clowns — sad-faced clowns with five o'clock shadows and tattered clothes — became popular. One of the most famous was Emmett Kelly ,whose "Weary Willie" was born in the Great Depression.
Source: Smithsonian Magazine
During the 1950s and 1960s, clowns became silly characters meant to entertain children. Thanks to TV programming, Bozo the Clown and his buddies were in every living room making children laugh. McDonald's even cashed in on the trend by creating its famous brand ambassador, the hamburger-loving Ronald McDonald, in 1963.
Source: Smithsonian Magazine
That all changed in the '70s when John Wayne Gacy — a registered clown who went by the name of "Pogo" — was arrested for sexually assaulting and killing more than 35 young men in the Chicago area. He told investigating officers, "You know...clowns can get away with murder." Gacy was executed in 1994.
Source: Smithsonian Magazine
In 1986, Stephen King wrote "It," a horror novel where a demon attacks children disguised as a clown. It was so popular that it was turned into a TV miniseries in 1990. Since then, clowns have become a common horror trope in movies like "Saw," "Funnyman," and "Clownhouse."
Source: Smithsonian Magazine
Some people believe the negative images of clowns are harming the clowning profession. The negative images "creat[e] a vicious circle of clown fear: More scary images means diminished opportunities to create good associations with clowns, which creates more fear. More fear gives more credence to scary clown images, and more scary clown images end up in circulation," Smithsonian Magazine writes.
Source: Smithsonian Magazine
But there’s evidence that kids actually do like clowns, especially sick children. Two separate studies showed that there was a beneficial health effect on sick children after playing with a therapy clown. It reduced their anxiety and some children even recovered faster.
Source: Smithsonian Magazine