Captain America: The First Avenger was the first Marvel Studios movie not set in the present day -- and that was initially a concern for the studio's advisory team. But Marvel Studios President Kevin Feige was able to successfully assuage their trepidations.
There was internal resistance making the film a period piece, according to Tara Bennett and Paul Terry's recently published The Story of Marvel Studios: The Making of the Marvel Cinematic Universe from Abrams Books. But Feige pushed back, responding, "What are you talking about? Raiders of the Lost Ark is a period piece."
But it wasn't just the World War II setting that was a concern -- the advisors were also worried about just how marketable the movie would be, specifically in regards to merchandising, and whether kids would be interested in buying toys based on 1940s-era technology. Feige in turn came up with an idea using a more modern Marvel story device that would make the era more interesting to younger Marvel fans.
"I thought, 'The Red Skull can use the Cosmic Cube to make all of these cool advanced weapons and vehicles,'" said Feige. "So it's a World War II movie, but you've got these enhanced motorcycles and tanks and Hydra soldiers blasting blue energy that you've never seen before. I remember getting in my car, going, 'That's how we can do it.'"
Set in 1942, 2011's Captain America: The First Avenger told the story of young but sickly Steve Rogers, played by Chris Evans, who volunteers in Doctor Abraham Erskine's experimental super-soldier program. The successful experiment transforms Rogers into a one-of-a-kind soldier with enhanced physical abilities who eventually adopts the identity of Captain America and fights alongside the Howling Commandos against Hydra.
Come 1945, though, Captain America suffers that fateful accident that plunges him into the Arctic Ocean and into a decades-long state of suspended animation. But Cap finally awakens in the present day, bringing the character into modern times as a founding member of Nick Fury's Avengers -- and circumventing any further concerns about a 1940s setting.
The film proved to be a major box office success, and wasn't even Marvel Studios' last period piece -- 2019's Captain Marvel was set in 1995. This year’s Black Widow, while set in more recent times, took place before the events of the preceding Avengers: Infinity War and Avengers: Endgame -- the latter of which features Natasha Romanoff’s death.
Source: The Story of Marvel Studios: The Making of the Marvel Cinematic Universe