Simplify the following text for a Grade 4 native English-speaking person.
Original: `` Simpsons Roasting on an Open Fire '' , also known as `` The Simpsons Christmas Special '' , is the first full-length episode of The Simpsons to air despite originally being the eighth episode produced for season one .
Simplified: Simpsons Roasting on an Open Fire is an episode of the Simpsons from Season 1 . It was the first full length episode of the Simpsons to be aired .