A Sicilian at the odds of the Queen's Knight. Morphy sacrifices his King's Bishop on the King's Knight's file, and after Black's only defence is exhausted he is forced into a mate on the 24th move.
13…Nxe5Had Black captured the Q's P. with Kt., White would have obtained a strong attack by sacrificing his K's B.
16…g6Fearing 17. Q. to K. R's 5th, &c. This was, in fact, Black's only move. 16. Q. to Q's 5th would not have answered, as in that case White could move 17. Q. to K. R's 5th, leaving the Bishop en prise, and winning immediately.
J. Löwenthal, Morphy's Games of Chess (1860) · Public domain · source