Question: "'Tis the Fifteenth Season" is the seventh episode of "The Simpsons"' fifteenth season, and the seventh Christmas-themed episode overall, this episode is notable as being the first to make reference to Lisa's Buddhism since she converted in which earlier Christmas episode, which is the sixth episode, of "The Simpsons"' thirteenth season?
Sentence (from "She of Little Faith"): It first aired in the United States on the Fox network on December 16, 2001.
Relevant evidence: No