Short answers, pulled from the story.
The most ancient clown figures on record come from the Fifth Dynasty of Egypt, around 2400 BC. Unlike later court jesters, these early clown figures traditionally served a socio-religious and psychological role, with the roles of priest and clown often held by the same person.
Joseph Grimaldi created the whiteface makeup design in 1801. He painted a white base over his face, neck, and chest, then added red triangles on the cheeks, thick eyebrows, and large red lips in a mischievous grin. According to his biographer Andrew McConnell Stott, it was one of the most important theatrical designs of the 1800s.
The Auguste is a red clown character developed around 1870 by Tom Belling senior while working for Circus Renz in Vienna. Belling designed the character as a foil for the white clown, featuring a red nose, white makeup around the eyes and mouth, and oversized clothes and shoes. The Auguste is typically an anarchist or fool of lower status than the white clown.
McDonald's derived its mascot clown Ronald McDonald from the Bozo character in the 1960s. Willard Scott, who had played Bozo from 1959 to 1962, performed as Ronald McDonald in 1963 television spots. The McDonald's trademark application for the character dates to 1967.
Coulrophobia is the fear of clowns, particularly circus clowns. The modern evil clown archetype was first popularized by the DC Comics character the Joker, who debuted in 1940, and later by Pennywise in Stephen King's novel It. The evil clown character is generally understood to play on the threatening or frightening quality that underlies the clown's appeal to young children.
Ecole Philippe Gaulier, a clown school in Etampes, France, was founded by master clown Philippe Gaulier. Its alumni include Sacha Baron Cohen, Roberto Benigni, Emma Thompson, Helena Bonham Carter, and Simon McBurney.