There is a  raging controversy in the chess world  because of the exact move order of Legal’s Mate.  We will try to help you sort it all out.  The below excerpt was take from Wiki page which you can read here :

We see here the  version of the game where Légal playing at rook odds (without Ra1) against Saint Brie in Paris 1750: He played…

1. e4 e5 2. Nf3 d6 3. Bc4 Bg4?! 4. Nc3 g6? 5. Nxe5 Bxd1?? 6. Bxf7+ Ke7 7. Nd5# 1–0

The above move order is found in most publications; however, research published at ChessBase suggests that the move order has been altered retrospectively in order to remove a flaw in the original game. Also the year 1750 is assumed to be wrong; it is more likely that the game was played in 1787, and that the original move order was:
1. e4 e5 2. Bc4 d6 3. Nf3 Nc6 4. Nc3 Bg4 5. Nxe5? Bxd1?? 6. Bxf7+ Ke7 7. Nd5# 1–0

Here the combination is flawed, as with 5… Nxe5 Black could have gained a piece. It is reported that Légal disguised his trap with a psychological trick: he first touched the knight on f3 and then retreated his hand as if realizing only now that the knight was pinned. Then, after his opponent reminded him of the touch-move rule, he played Nxe5, and the opponent grabbed the queen without thinking twice.

If you would like to read about Legal’s famous pupil Philidor you can do so here.