From the LA Times:

Joe Simon, a pioneer figure in American comic books who had a defining career moment in March 1941 when he gave the world a star-spangled superhero named Captain America, has died. He was 98.

Simon died Wednesday in New York City after a brief illness, according to a statement from his family, and his death adds a solemn final note to the 70th anniversary of his greatest creation, Captain America, who leaped across the big screen this summer with the Marvel Studios film "Captain America: The First Avenger." That film grossed $368 million in worldwide box office and earned strong reviews despite the early skepticism about the 21st century prospects of a Roosevelt-era character who looks like a walking American flag.

Simon created Captain America with Jack Kirby, a titan figure in American comics, and the two would work together for various publishers over several decades. Their shared credit eventually took on an esteemed aura as the medium edged its way from disposable pulp confection to something more ambitious and a sort of monthly American mythology.