‘A fictitious account of this meeting was written by Marie Aycard for the "Palamède" in 1843, and in the course of the story the game to which I have referred is given. It is pretended that the Chevalier de Lorenzy had taken it down at the time, and that M. Doazan had supplied it from the MS. All this is very circumstantial, but the only piece of truth in it is the fact that M. Doazan had supplied the game from a MS in his possession. But this MS was not the work of de Lorenzy, neither did it contain eighteenth-century games. The only MS in Doazan’s possession was the so-called “Doazan MS”, which was described in the "Palamède" in 1843; and at a later time, after William Lewis had publicly expressed doubts as to the genuineness of the MS, it was seen by v.d. Lasa in 1855. V.d. Lasa extracted the games, and circulated them among his friends in a lithographed edition, under the title of "Recueil de Parties d’Echecs, Bruxelles, 1855". The MS has disappeared since the sale of M. Doazan’s library in 1865, but, thanks to v.d. Lasa, we know exactly what the MS was, and what it contained. It was an Italian compilation of the early seventeenth century, the work of some admirer or companion of that Polerio who accompanied Leonardo – il Puttino – on his journey to Madrid to play Ruy López, about 1575. That the supposed game Rousseau v the Prince de Conti was obtained from this MS is quite clear, for it occurs there from the first move to the last. There, however it is given as from the play of the Spaniard Busnardo, a contemporary of Ruy López. The Doazan MS stands in close connection with an Italian MS at Paris (It. 955), and the same game occurs in this MS, with the title, “Altra manera d’uscire del busnardo”. It is clear that the modern ascription of the game is as fictitious as the story in which Aycard set it, and that later writers have made the easy mistake of treating chess fiction as chess history.’>

From Edward Winter's "Jean-Jacques Rousseau and Chess": http://www.chesshistory.com/winter/...