Before being introduced in 1997, interleague play only occurred in spring training and exhibition games.
But for one player that entered Cooperstown wearing a Cubs hat, the crosstown series has always held bragging rights regardless if the games meant something in the standings or not.
Billy Williams, a Six-time All-Star and National League Rookie of the Year with the Cubs in 1961, likened the Cubs-White Sox rivalry to a famous feud during the Civil War.
"A long time ago we used to play the White Sox at Sox Park and that was always fun," Williams said. "You can't look at the record each team has because I always compare it with the Hatfield and McCoys. It's really something."
Check out the rest of Williams' comments in the video above.