Marvel Entertainment has pushed back the release dates of its comic book superhero films from just a few months to a full year.

"Thor" has been given the biggest delay date so far. Marvel pushed back its date from July 2010 to June 17, 2011.

"The Avengers" nixed its planned July 2011 release date for May 4, 2012 instead, while "The First Avenger: Captain America" has been postponed for two months and will now grace the theaters on July 22, 2011.

Marvel didn't give a reason for the shift, though it said that the change "maximizes the visibility of our single character-focused films, leading to the highly anticipated release of the multi-character 'The Avengers' film in 2012."

"Iron Man 2" release date remains May 7, 2010. The film studio also announced the release date of "Spider-Man 4" on May 6, 2011.