Steve Ditko, who helped create Spider-Man and who, along with Stan Lee and Jack Kirby, was one of the three figures behind Marvel Comics’ rebirth in the 1960s, was found dead in his home last week, reports The Hollywood Reporter. Ditko was 90.

As a staff illustrator for Marvel, Ditko designed the red-and-blue costume, underarm webbing and bug-eyed mask that distinguishes Spider-Man more than 50 years after his debut in 1962’s Amazing Fantasy #15. At the time, Marvel, under Lee’s direction, was experimenting with its line of Silver Age horror and suspense titles, like Journey into Mystery and Strange Tales, to develop superheroes that today earn millions as box office attractions.

Ditko is most famous for creating two: Spider-Man and Doctor Strange, who first appeared in 1963. Ditko also created many of their longtime adversaries, including the Green Goblin, Baron Mordo, the Sandman, the Dread Dormammu, the Vulture and the Lizard.

Stephen J. Ditko was born Nov. 2, 1927 in Johnstown, Pennsylvania. He began his professional career in 1953, moving to Atlas Comics, Marvel’s forerunner, beginning with Journey Into Mystery #33, which would become the vehicle for Marvel’s Thor a decade later.

His creative breakthrough came with Spider-Man, a one-shot experiment that panned out spectacularly. Kirby had also drawn treatments of the character, but Lee preferred the lanky and vulnerable figures Ditko had prepared to tell what was idealized as the story of an ordinary teenager bestowed with great power.

A surprising sales success, Spider-Man returned six months later, in March 1963, in a dedicated title. Ditko illustrated Spider-Man throughout the 1960s, including Amazing Spider-Man #33 (“If This Be My Destiny”) the culmination of a three-issue epic in which Spider-Man escapes from Doctor Octopus’ underwater lair to save his dying Aunt May. The arc is considered one of the defining works of Spider-Man’s early canon and the “Marvel Age” of comic books it ushered in.

Elsewhere, Ditko brought his surreal influence to bear on Strange Tales and Doctor Stephen Strange, who first appeared in the magazine’s July 1963 issue. Ditko illustrated Strange and his bizarre, mystical enemies until leaving Marvel in 1966. Though never confirmed, and Ditko never discussed it, it has long been said that he and Lee had a falling out. Ditko moved on to work for Charlton and then DC Comics, where he co-created The Creeper for Showcase #73 in 1968.

Ditko returned to Marvel in the late 1970s but did not have roles in any of the publisher’s major books of the day. Then, in The Amazing Spider-Man’s 1988 annual, Marvel’s new editor-in-chief Tom DeFalco and Ditko created a new superhero, Speedball, drawing on Spider-Man’s teenage superhero themes and Ditko’s original style of illustrating him. Ditko effectively retired from comic books in 1998.

Ditko never married and is not known to have any survivors. He is a 1990 inductee of the Jack Kirby Hall of Fame and a 1994 inductee to the Will Eisner Hall of Fame.