Krusty the Clown

Context: Krusty first appeared in "The Krusty the Clown Show", one of The Simpsons shorts from The Tracey Ullman Show that first aired on January 15, 1989. The character was partially inspired by TV clown "Rusty Nails" whom The Simpsons creator Matt Groening and director Brad Bird watched as children while growing up in Portland, Oregon. Groening describes Rusty Nails as being a sweet clown whose show sometimes had a Christian message, but whose name scared Groening. Dan Castellaneta based his voice characterization on Chicago television's Bob Bell who had a very raspy voice and portrayed WGN-TV's Bozo the Clown from 1960 to 1984. Many events in Krusty's life parallel those of comedian Jerry Lewis, including his Jewish background, addiction to Percodan, and hosting of telethons. When asked, Groening has simply noted that "[Simpsons] characters are collaborations between the writers, animators, and actors" without specifically confirming or denying the association. Krusty's appearance and design is essentially that of Homer Simpson with clown makeup. Groening said that "The satirical conceit that I was going for at the time was that The Simpsons was about a kid who had no respect for his father, but worshipped a clown who looked exactly like his father", a theme which became less important as the show developed. One concept initially saw Krusty being revealed as Homer's secret identity but the idea was dropped for being too complex and because the writers were too busy developing the series. There are two instances of the one assuming the identity of the other. In a (non-canonical) Butterfinger commercial, pertaining to a contest for $50,000 to find out who stole Bart's Butterfinger, a captured Homer appears to be the culprit until Maggie pulls off a mask, revealing Krusty. In the episode "Homie the Clown", Homer goes to Clown College and dresses up as and is confused with Krusty. Krusty was originally just a normal man wearing clown makeup, but David Silverman noted that "at some point, we decided he looked [like a clown] all the time." The producers had long discussions about whether or not Krusty would always remain in his clown makeup but eventually decided that it did not matter. The writers had tried showing Krusty's real face a few times in early episodes, but decided that it did not look right, although his real face was seen in "Krusty Gets Busted" and "Like Father, Like Clown". Later episodes made jokes about Krusty's face. In "Homer's Triple Bypass", Krusty reveals that his "grotesque appearance" is the result of multiple heart attacks. Homer remarks that he seems fine, and Krusty replies, "This ain't makeup." In "Bart the Fink", he abandons an idea to sail away with a new identity and swims towards shore, leaving a trail of yellow makeup in his wake and his natural white face underneath. On shore, he shakes off his black hair, revealing his natural green clown hair, and removes his normal-looking fake nose to reveal his natural red bulbous clown nose underneath. CANNOTANSWER

Question: When was Krusty created?
Answer: Krusty first appeared in "The Krusty the Clown Show", one of The Simpsons shorts from The Tracey Ullman Show that first aired on January 15, 1989.