This one’s tough. Last night in a post on Twitter artist John Romita Jr. announced that his father, the legendary artist John Romita Sr., has died. According to Romita Jr., his father “passed away peacefully in his sleep.” Romita Sr. was 93 years old.

“I say this with a heavy heart,” Romita Jr. said in the post. “My father passed away peacefully in his sleep. He is a legend in the art world and it would be my honor to follow in his footsteps. Please keep your thoughts and condolences here out of respect for my family. He was the greatest man I ever met.”

Tributes to John Romita Sr., who for a generation of readers was the definitive Spider-Man artist, have poured in on social media from figures across the comics industry. Here’s just a small handful of them:

John Romita Sr.’s career, which primarily consisted of work for Marvel Comics, spanned over sixty years. His first comics work came in 1949, when Romita Sr. was 19 years old, on the Eastern Color Printing series Famous Funnies, and soon after he began working for publisher Timely Comics, the company that would become Marvel. Throughout the ’50s and early ’60s Romita Sr. worked on romance and war comics for Timely/Marvel and DC Comics, before joining Marvel full-time in 1966, first as the artist on Daredevil and then taking over for departing artist Steve Ditko on Amazing Spider-Man.

Romita Sr. was joined primarily by inkers Mike Esposito and Jim Mooney during his run as penciller/layout artist on Amazing Spider-Man, which began with 1966’s issue #39 and ran through 1973’s issue #119. During that time Romita Sr. designed and helped introduce Marvel mainstays including Mary Jane Watson, The Kingpin, The Shocker, and more.

Mary Jane Watson’s iconic first full appearance in AMAZING SPIDER-MAN #42, by Stan Lee, John Romita Sr., and Sam Rosen

In ’73 John Romita Sr. became Marvel’s Art Director, a position he held through the rest of the ’70s and ’80s. In that role, he designed the looks for a number of iconic Marvel characters including Wolverine, The Punisher, Bullseye, and Black Widow, among others.

Romita Sr. remained active as an artist, drawing short stories and doing cover work well into the 2000s. He was inducted into the Will Eisner Awards Hall of Fame in 2002.

The Beat offers its sincere condolences to John Romita Sr.’s family and friends.