Banned for DC Comics/Warner Bros. slowly expanded the character's supporting cast, powers, and trappings throughout the years. Superman's backstory was altered to allow for adventures as Superboy, and other survivors of Krypton were created, including Supergirl and Krypto the Superdog. In addition, Superman has been licensed and adapted into a variety of media, from radio to television and film, perhaps most notably portrayed by Christopher Reeve in both Richard Donner's Superman: The Movie in 1978, and the sequel Superman II in 1981, which garnered critical praise and became Warner Bros.'s most successful feature films of their time. However, the next two sequels, Superman III and Superman IV: The Quest for Peace, did not perform as well at the box office. The motion picture Superman Returns was released in 2006, which although relatively unsuccessful within the United States, returned a performance at the international box office which exceeded expectations.[10] In the seven decades since Superman's debut, the character has been revamped and updated several times.