Start at the 3:25 mark
John Mulaney: Leap Year began in 45 B.C. under Julius Caesar. This is true, he started the Leap Year in order to correct the calendar and we still do it to this day.
Another thing that happened under Julius Caesar, he was such a powerful maniac that all the senators grabbed knives and they stabbed him to death. That would be an interesting thing if we brought that back now.