Donald Sutherland voiced the historian in this episode. The script was specifically written with him in mind playing that part. Sutherland wanted to do the voice recordings as one would do a film and start in the middle of the script, so that he could get to know the character, but that idea was abandoned. In the episode, Lisa joked she was getting over her "Chester A. Arthuritis", a play on the word "arthritis" and the name of Chester A. Arthur. Sutherland ad-libbed the line "you had arthritis?", and the producers liked it so much that they kept it.