The long-running animated show “The Simpsons” celebrated a monumental mark yesterday, as the programs 500th episode aired on Fox. In sum, the show has run for roughly 200 hours total and spanned 23 seasons. Guest voices for the animated program have come from a pool of Oscar winners, novelists, politicians, singers and entertainers, and many others. It has also made billions of dollars for the Fox network and millions of dollars for its creators.

The celebration to mark the 500th episode was done in grand style, as Fox ran an 86-hour string of episodes in order to break the longest record for a television marathon. It was such a big deal that people competed for a $10,500 prize to see who could watch the longest. Al Jean, who was the shows executive producer in the third and fourth seasons, and then again from the 13th season to present, sat down to talk about the history of the show and some of the nuance surrounding it.

One of the most interesting things he talked about was the switch from a focus on Bart to one that centered more on Homer. Asked if there was a plan from the beginning to feature Bart, he noted, “Well, he was the one that really popped with the general public first. I think with the writers it was always slightly easier to pitch Homer ideas because Homer was an adult male and he was somebody they could relate to. But Barts a great character. Two of the episodes that center around him and the school are still really popular. There was never a conscious change. We just do episodes that we think are funny and theres always a point where we think Hmm, we had too many Homers in a row. Lets break it up. I like doing Lisa ones too. They’re all great characters.”