Asking Alexandria were never metalcore lol; they were post-hardcore/hardcore. Most people started hearing about metalcore when As I Lay Dying formed in 2000, or when Killswitch Engage formed in 1999. The biggest things that brought attention and fame to metalcore were Parkway Drive back in 2004, or when As I Lay Dying released their album "Shadows Are Security" in 2005, and then again when AILD released "An Ocean Between Us" in 2007.