EDITOR'S NOTE: This article is part of a series, "Countdown to Endgame," which looks back at the films of the Marvel Cinematic Universe leading up to Avengers: Endgame.
With two massively successful Iron Man films and a moderately successful Hulk reboot under its belt, Marvel Studios began development on the most ambitious projects of its early years with its next three films: Thor, Captain America: The First Avenger and The Avengers.
The first film would feature a mythological figure blending the worlds of science fiction and fantasy that eschewed traditional conventions in mainstream superhero films, while the second would be almost entirely a period piece set during the height of World War II starring the least cynical superhero in the entire Marvel Universe. Upon the new characters' introduction, the studio would then deliver on its longstanding promise to include them all in the most ambitious cinematic crossover at that time.
For a studio whose first film was only four years old, this was an extraordinary risk, the concept of the Marvel Cinematic Universe little more than a novelty with cameo appearances and Easter eggs at that point. It also meant wider genre shifts, with Thor tenuously featuring the MCU's first serious exploration in sci-fi and fantasy, while Captain America was a war film, just one that featured a star-spangled hero wielding an indestructible shield. For a shared cinematic universe still in its relative early stages, it was a bold move, especially as behind the scenes troubles began to plague Thor.
Marvel Studios had originally signed Matthew Vaughan to helm the first Thor film, though the filmmaker ultimately left the project over budget concerns and directed X-Men: First Class instead. While Guillermo del Toro was approached, he similarly opted to write and direct The Hobbit before being himself being replaced by Peter Jackson. It was in classically trained Kenneth Branagh that Marvel Studios finally found its Thor director, with the release date pushed from July 2010 to May 2011 to accommodate the delays.
After Daniel Craig turned down the title role due to his commitments to the James Bond franchise, Branagh cast relative unknown actors Chris Hemsworth and Tom Hiddleston as Thor and his adopted brother, Loki, while filling the supporting cast with more established actors, including Natalie Portman, Anthony Hopkins and Rene Russo, to lend the film more gravitas.
In the promotional campaign leading up to the film's release, the cast and crew downplayed the more mythological, fantasy elements of the character. Instead, Asgard and its inhabitants were referred to as aliens from a faraway world that visited Earth millennia ago and inspired Norse myths rather than actually being gods themselves, with their advanced technology indistinguishable from magic to more primitive civilizations.
To help sell the out-there concept of the property, much of Thor is a fish out of water story with comedic flourishes as the Prince of Asgard is cast out by his father Odin to Earth, where he learns humility while growing close to humanity through Jane Foster and her colleagues. After dealing with Loki's inevitable betrayal, Thor would prove himself worthy of regaining his powers and vow to protect Earth whenever it needed him.