Well, not Twain himself, but the mullets he ascribed to nobility in A Connecticut Yankee in King Arthur’s Court, that is…

About bedtime I took the king to my private quarters to cut his hair and help him get the hang of the lowly raiment he was to wear. The high classes wore their hair banged across the forehead but hanging to the shoulders the rest of the way around, whereas the lowest ranks of commoners were banged fore and aft both; the slaves were bangless, and allowed their hair free growth.
(the beginning of Chapter 27: The Yankee and the King Travel Incognito)