Dwig
Well-known
twice according to the lore. It seems when Edmond Halley, of Halley's Comet fame, finally succeeded in pushing Newton to publish his work, Newton had forgotten the exact method he had used to develop "fluctions", as he termed it. He had to work it all out again.
All of the optical gymnastics that have been developed to reduce lens based chromatic aberration decend from Newton's experiments into the nature of light and color.