This trap mate involves the offer of a Queen sacrifice, and is historically credited to the French player M. de Kermar, Sire de Légall (1702-1792) (spelling of his last name varies between Légall and Légal). Sometimes it is referred to as the Blackburne Trap, because the English player Joseph Blackburne (1859-1951) trapped many players with it! There are a number of different move orders in a number of different openings in which it might arise. This trap is well worth knowing so you don't fall victim to greed, and maybe you can even take advantage of your opponent's greed!!!
The mating pattern offering a Queen sacrifice to obtain the mating trap with the two Knights and a Bishop is from Légal vs. St Brie 1750 (some references say only about 1750).
