Darwin had several nicknames. As a young naturalist on board the HMS Beagle, he was called “Philos” because of his intellectual pursuits and “Flycatcher” when his shipmates tired of him filling the ship with his collections. Later in his life, when he became a leader in the scientific community, journalists referred to him as the “Sage of Down” or the “Saint of Science,” but his friend Thomas Henry Huxley privately called him the “Czar of Down” and the “Pope of Science.” His own favorite nickname was “Stultis the Fool,” and he often signed letters to scientific friends with “Stultis.” This name referred to his habit of trying experiments most people would prejudge to be fruitless or fool’s experiments.