Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5/3...a6/4. Ba4/4...Bc5

4...Bc5
Black develops the bishop and attacks the f7 pawn

5.Nxe5 is the main move

1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Bc5