American actor Kevin Conroy, the man behind the serious voice of the superhero Batman, has died at the age of 66, according to his representative Gary Mireanu, according to CNN, citing Agerpres.

Conroy died Thursday, shortly after being diagnosed with cancer, Mireanu said. In turn, the information was confirmed by DC Comics.

Conroy’s work in the role is the foundation of every iteration of Batman that popular culture has seen since.

He played Bruce Wayne and his alter ego Batman for years on television, including the beloved Batman: The Animated Series, and his influence can be heard in the performances of Christian Bale, Robert Pattinson and other actors who brought this popular character to life.

But few actors can say they’ve played Batman as often as Conroy, appearing in more than 400 television episodes as the voice of the Dark Knight.