The expression “to get cold feet” was by the editors of A Dictionary of Americanisms (1951).
But Kenneth McKenzie, professor emeritus of Italian at Princeton, has found a much older instance of its use.
“This expression can hardly have originated in the 1890’s, as you state, for it is found in Ben Jonson’s Volpone (1605), where he refers to it as a ‘Lombard Proverb.’ Some years ago I published a short article on the subject, ‘Ben Jonson’s Lombard Proverb,’ in Modern Language Notes, Vol XXVII (1912), p. 263. There seems to be no doubt that Jonson heard it used by some Italian friend.”
The pertinent part of this article reads: “In the second act of the play, Volpone, disguised as a ‘mountebank doctor,’ explains to the crowd why he has fixed his bank in an obscure nook of the Piazza of St. Mark’s instead of a more prominent place:
Let me tell you: I am not, as your Lombard proverb saith, cold on my feet; or content to part with my commodities at a cheaper rate than I am accustomed: look not for it.
In other words, he is not so ‘hard up’ as to be obliged to sell his wares at a sacrifice.”
Professor McKenzie’s article goes on to relate that the proverb, Avegh minga frecc i pee, to have cold feet, is still used in Lombardy, with the figurative meaning, “to be without money.” “And if a card player, as a pretext for quitting the game in which he has lost money, says that his feet are cold, the expression might come to mean in general ‘to recede from a difficult position,’ or more specifically, ‘to have cold feet.'”