Until the 19th century, this line was the main line of the Italian Game. Dubbed the
Giuoco Piano ("Quiet Game") in contrast to the more aggressive lines then being developed, this continues 4.d3, the positional
Giuoco Pianissimo ("Very Quiet Game"), or the main line 4.c3 (the original Giuoco Piano) leading to positions first analyzed by Greco in the 17th century, and revitalized at the turn of the 20th by the Møller Attack. 4.0-0 will usually
transpose into the Giuoco Pianissimo after 4...Nf6 5.d3, while 4.Nc3 Nf6 is a transposition into the
Four Knights Game. Another option for White is the aggressive
Evans Gambit (4.b4), a popular opening in the 19th century which is still occasionally played. The
Italian Gambit (4.d4) may transpose into the
Scotch Gambit after 4...exd4; however, this move order allows Black the option of 4...Bxd4, so if White wants a Scotch Gambit, 3.d4 is usually preferred. The
Jerome Gambit (4.Bxf7+) is unsound. ==Two Knights Defense: 3...Nf6==