This is not a joke: an English composer by the name of William Bastard (no relation to William the Conqueror) published a piano trio in 1908. The score can be found below for free viewing and download:
W. Bastard - Piano Score - Trio (sol mineur) pour piano, violon et violoncelle. Op. 3. -
The Bastard Trio might pair well in recital with some piano works of Ludwig Schytte, who lived around the same time.
(Via Bob Silverman)
Update: there was a comment on Facebook as to a possible Norwegian birth under the name Ole Bastard, but I somehow doubt this.