Complex sentence: However, he got into a fistfight with Hank Greenberg in Lakeland, Florida, after an argument in which Greenberg made a comment about Sewell's southern heritage, and Sewell responded with a comment about Greenberg's Jewish heritage.
Split into simpler sentences: However, he got into a fight with Hank Greenberg in Lakeland, Florida. According to Sewell, Greenberg made a comment about Sewell's southern heritage, and Sewell responded with a comment about Greenberg's Jewish heritage.