Churchillian Drift
n.— «Long ago, I coined the term “Churchillian Drift” to describe the process whereby the actual originator of a quotation is often elbowed to one side and replaced by someone more famous. So to Churchill or Napoleon would be ascribed what, actually, a lesser-known political figure had said. The process occurs in all fields.» —“Policing Word Abuse” by Nigel Rees Forbes Aug. 13, 2009. (source: Double-Tongued Dictionary)
Further reading
You know that Yogi Berra quote about how Nobody ever comes here; it’s too crowded? Actually, the first person to use this was actress Suzanne Ridgeway, who appeared in several movies with The Three Stooges. A new book shows that many well...
Mike in Glasgow, Kentucky, wonders about a catchphrase used in British comedies: I go to the foot of the stairs. The Oxford Dictionary of Catchphrases (Amazon) compiled by Anna Farkas and several books by catchphrase collector Nigel Rees both point...