Upon discovering a French translation of this story, Twain back-translated the story into English, word for word, retaining the French grammatical structure and syntax. He then published all three versions under the title "The Jumping Frog: in English, then in French, and then Clawed Back into a Civilized Language Once More by Patient, Unremunerated Toil".
In "Private History of the ‘Jumping Frog’ Story", Twain recounts some background to the tale—in particular, his surprise to find that the story bore a striking resemblance to an ancient Greek tale. He wrote:
Now, then, the interesting question is, did the frog episode happen in Angel’s Camp in the spring of ‘49, as told in my hearing that day in the fall of 1865? I am perfectly sure that it did. I am also sure that its duplicate happened in Boeotia a couple of thousand years ago. I think it must be a case of history actually repeating itself, and not a case of a good story floating down the ages and surviving because too good to be allowed to perish.
Later, however, in November 1903, Twain noted:
When I became convinced that the "Jumping Frog" was a Greek story two or three thousand years old, I was sincerely happy, for apparently here was a most striking and satisfactory justification of a favorite theory of mine—to wit, that no occurrence is sole and solitary, but is merely a repetition of a thing which has happened before, and perhaps often.... By-and-by, in England, after a few years, I learned that there hadn't been any Greek frog in the business, and no Greek story about his adventures. Professor Sidgwick [in his textbook for students learning to translate English texts into Greek, Greek Prose Composition, p. 116] had not claimed that it was a Greek tale; he had merely synopsized the Calaveras tale and transferred the incident to classic Greece; but as he did not state that it was the same old frog, the English papers reproved him for the omission. He told me this in England in 1899 or 1900, and was much troubled about that censure, for his act had been innocent, he believing that the story's origin was so well known as to render formal mention of it unnecessary.
But in his "Note To The Thirteenth Edition" (1907), among "hearty .. thanks for the help received", Prof. Sidgwick still failed to acknowledge his use of the Twain tale.