Twain was very strong in his belief that Shakespeare had nothing to do
 with his "Works." This is set forth in his "Is Shakespeare Dead???". His
 radical literary convictions are discussed in a site dwelling on the
 evidence for a different authorship. Other famous literary characters
 were similarly convinced. For a start, see:

 http://fly.hiwaay.net/~paul/pennl/pamphlet.html

 Penn Leary