PHILADELPHIA - In creating Captain America, the latest Marvel superhero to bound onto the big screen this summer, Joe Simon and Jack Kirby relied on reality for their inspiration.

"With Captain America, the villain came first. Jack and I read the newspapers, and knew what was going on over in Europe. And there he was -- Adolf Hitler, with his ridiculous moustache, high-pitched ranting and goose-stepping followers," Simon recalled in a recent interview. "He was the perfect bad guy, much better than anything we could have made up, so what we needed was to create his ultimate counterpart."

And so was born Steve Rogers, a scrawny would-be soldier with a 4-F physique and the stalwart heart of a warrior, even if the Army would not take him.

The character who would one day become an Avenger and form a cornerstone of the Marvel Universe came to life in the pages of "Captain America Comics" in December 1940, giving Hitler a hard right hook and capturing the imagination of a nation waiting for war.

"In (my) autobiography, I describe the way Jack and I developed our collaboration, often jumping around the room tossing ideas at each other, 'Let's do it this way!' and 'Let's take it that way!' and before we knew it, we had the entire first issue ready to show Martin Goodman at Timely Comics," Simon said, recounting a tale from "Joe Simon, My Life in Comics," published earlier this year.

"We based Cap's sidekick (Bucky) on an old high school buddy of mine, and Martin loved it!" he added.

The character proved a popular hit -- the first issue sold a million copies and put Timely Comics solidly among newsstand favourites, a position held through the 1950s before it became Marvel in the 1960s.

While not the comic book world's first patriotic superhero, Captain America quickly became the most popular, inspiring dozens of imitators, said Tom Brevoort, Marvel's senior vice-president of publishing.

"This had a lot to do with the kinetic visual style that Simon and Kirby employed on the strip -- it was the most exciting-looking comic book of its era, and set the tenor for all superhero art that came thereafter," Brevoort explained.

Mark Evanier, a comics historian, said that it was Captain America's sales that helped put Timely -- just one of a plethora of publishers -- on a firm footing that enabled it to survive the shakedown that came after the war.

Now, 71 years on, Rogers is still going strong, both in comic shops and now in theatres with Paramount's "Captain America: The First Avenger."

But it's not the first time the shield-slinging patriot has been on the big screen. In 1944, his adventures were made into a serial that were broadcast on TV in 1953. In 1990, there was also a low-budget film about the character.

"He's absolutely a seminal bedrock character for the Marvel line," said Brevoort. "And he's a concept that anybody can understand. Even people who've never read a Captain America story before intuitively comprehend what he's about and what he stands for, and no matter where you happen to sit along the political spectrum in this country, Captain America represents something to you. He's astonishingly universal."

The last time Captain America drew national headlines was in 2007 when he was gunned down on the steps of a U.S. courthouse after a prolonged battle over personal rights that pitted Marvel heroes against each other.

Though the death did not stick -- they seldom do in comics -- the story line by Ed Brubaker pushed the character back into the national consciousness.

Simon isn't surprised, even though after World War II, Cap and other superheroes found themselves edged out by comic book buyers in favour of Western, romance and horror comics.

"But through it all, I knew we had a terrific hero," said Simon. "Cap is one of the great comic book icons, and as dangerous as the world is today -- more than it was in the 1940s -- we need him around more than ever to act as our moral compass."