We know they are learning history because of the history book on the teacher's desk.
While I think this was just Chip's lame excuse to put the word 'ass' in a comic strip, he brings up a good point. We only believe Cleopatra was killed by an asp (she committed suicide) because that's what people of the time wrote and other biographers and historians agree. Maybe she was kicked in the face by a donkey or something and people were like, "she needs a more noble death, she's the queen of Egypt for Ra's sake!" and poof, suicide-by-asp was born.
