SF fans have been writing songs (sometimes parodies, sometimes to original music) since at least the 1940s, but they didn't start calling them "filksongs" until the early 1950s. That was when Lee Jacobs mistyped "folk" as "filk" in a fanzine article on folk music. Karen Kruse (later Karen Anderson) liked the word and used it to describe the long-standing fannish phenomenon in an article for "The Zed #780," her SAPSzine (December 1955), and the use caught on.
Free Style Twippledop and Other Editorial Oozings (The Zed #780)
(including an essay on filksong writing)
by Karen and Poul Anderson writing as
P. A. Kingsley
From the June 1955 mailing of SAPS.
Scans supplied by Lee Gold with
permission of Karen Anderson.
In the 32nd mailing of the Spectator Amateur Press Society (June, 1955), Karen Anderson contributed The Zed #780, which mentioned Arb Kingsley who "after one happy [nuclear] fizz party, has taken to fandom. He will appear here regularly, and all fids to me! You ought to hear his filk songs, too."
Further investigation with Karen elicited the information "'Petronius Arbiter Kingsley' was a made-up name for a nonexistent contributor to The Zed. Zed is an alternate name for the last letter of the alphabet; the fanzine's full but not-always-used title was Die Zeitschrift für Vollstandigen Unsinn, The Journal for Utter Nonsense. Its first issue was numbered 771. 'Voldesfan,' for Volatile Destructive Fan, was my coinage as an antonym for Sercon-fan." In a later email, she said, "If it's bylined by Kingsley, it was probably by both Poul and me."
Traveling yet further back in time, to the 26th SAPS distribution, Winter, 1953, on page #22 of Die Zeitschrift für Vollstandigen Unsinn #774 by Karen Kruse Anderson is...the first-known song published as a filk song [123k scan] - written (see the note in The Zed #780) by Poul Anderson.
--Lee Gold
![the first-known song published as a filk song [123k scan]](barbarousAllen.gif){kind=link}