“Wittgenstein's personality dominated these meetings. I doubt that anyone in the class failed to be influenced by him in some way. Few of us could keep from acquiring imitations of his mannerisms, gestures, intonations, exclamations. These imitations could easily appear ridiculous when compared with their original.”

Cassandra (1860)
Context: The great reformers of the world turn into the great misanthropists, if circumstances or organisation do not permit them to act. Christ, if He had been a woman, might have been nothing but a great complainer. Peace be with the misanthropists! They have made a step in progress; the next will make them great philanthropists; they are divided but by a line.
The next Christ will perhaps be a female Christ. But do we see one woman who looks like a female Christ? or even like "the messenger before" her "face", to go before her and prepare the hearts and minds for her?
To this will be answered that half the inmates of Bedlam begin in this way, by fancying that they are "the Christ."
People talk about imitating Christ, and imitate Him in the little trifling formal things, such as washing the feet, saying His prayer, and so on; but if anyone attempts the real imitation of Him, there are no bounds to the outcry with which the presumption of that person is condemned.

Hawthorne and His Mosses (1850)
Context: It is better to fail in originality, than to succeed in imitation. He who has never failed somewhere, that man can not be great. Failure is the true test of greatness.
Context: It is better to fail in originality, than to succeed in imitation. He who has never failed somewhere, that man can not be great. Failure is the true test of greatness. And if it be said, that continual success is a proof that a man wisely knows his powers, — it is only to be added, that, in that case, he knows them to be small. Let us believe it, then, once for all, that there is no hope for us in these smooth pleasing writers that know their powers.

in The Erasmus Reader (1990), p. 130.
Ciceronianus (1528)

Page. 70.
Islam at the Crossroads (1934)

Homage to the square' (1964), Oral history interview with Josef Albers' (1968)

"Imitation and Gender Insubordination" in Inside/Out (1991) edited by Diana Fuss

L’écrivain original n’est pas celui qui n’imite personne, mais celui que personne ne peut imiter.
The Oxford Dictionary of Quotations (1979) 3rd edition
Variant translations:
The original style is not the style which never borrows of any one, but that which no other person is capable of reproducing.
As translated by Charles I. White (1856) Part 2, Book 1, Chapter 3
An original writer is not one who imitates nobody, but one whom nobody can imitate.
Bartlett's Familiar Quotations (1980) 15th edition.
Le génie du Christianisme (1802)

On art versus life in “Berkeley world premiere for Naomi Iizuka play” https://www.sfgate.com/performance/article/Berkeley-world-premiere-for-Naomi-Iizuka-play-3271229.php in SF Gate (2010 Mar 4)

1960s
Source: 'A period of Exploration', McChesney, as quoted in The New York school – the painters & sculptors of the fifties, Irving Sandler, Harper & Row, Publishers, 1978, p 35