After declining to develop a line of Star Wars action figures in 1976 and failing to reach an agreement to develop movie tie-in toys for Conan the Barbarian in 1980, Mattell struggled to introduce a new line of action toys to capitolize on the growing action figure market. Designer Roger Sweet claims to have developed the origins of the Masters of the Universe toy line by creating three prototype toys featuring a barbarian, a soldier, and a spaceman. Mattel chose to further develop the line around the barbarian figure and the related asthetics.
The mythology was further expanded by writer Donald F Glut and artist Earl Norem, who collaborated to create the production art and a series of mini-comics that were distributed with the toys. The stories were short and simple, intended primarily to establish the characters of the attatched figures. They depicted He-Man as a wandering barbarian on the desolate world of Eternia after a great war opened rifts between multiple dimensions (explaining the franchise's tendency to meld fantasy with science fiction elements.) The evil warlord Skeletor travels through one such rift and attempts to conquer Castle Grayskull to obtain its mysterious power. In order to repel Skeletor, The Sorceress (sometimes named The Goddess in early comics) grants magical powers and weapons to He-Man to increase his strength. He-Man's allies are established as Man-At-Arms, the Eternian master of weapons, and Teela, the adopted daughter of Man-At-Arms. Other elements of the plot revolve around the two halves of the Power Sword, one of which is wielded by He-Man and the other found by Skeletor. Skeletor attempts to gain both halves, as wielding both will grant him access to Grayskull.
Another eventual plot of these mini-comics revolved around the distant past of Eternia (sometimes called Preternia) and was released in toys under the title The Powers of Grayskull--The Legend Begins. This unfinished plot introduces new characters and plots such as King Hiss and his evil Snake Men and his battles against the Elders. He-Man and The Sorceress are pulled back in time, along with Skeletor. Hiss and Skeletor try to form an alliance, and He-Man battles them while in disguise. Eventually a shadowy figure arrives to send the Snake Men back to their base and send the time traveler's home. While the story was never finished, some details are known. The shadowy figure was a wizard named He-Ro, who is one of He-Man's ancestors. The main antagonist of the abandoned storyline and associated toys was meant to be an evil wizard named Keldor, who would later be revealed to be He-Man's uncle, and the previous form of Skeletor.
DC Comics published stories based on Masters of the Universe begining in 1982 which further expanded the mythology, intoducing the Kingdom of Eternia and its royal family, and the fact that He-Man is the alter ego of the young Prince Adam. Adam is chosen by The Sorceress to be Eternia's defender, transforming into He-Man to keep his identity secret from all other than The Sorceress and Man-At-Arms. The first appearance of He-Man in DC Comics was as an insert in DC Comics Presents #47 in a story involving Superman being transported to Eternia.
The comic rights to Masters of the Universe eventually were granted to Marvel Comics in 1986 for a short lived series under the Star Comics label. The series mainly focussed on late additions to the toy line.
1983 marked the first televised version of the franchise in the animated series He-Man and the Masters of the Universe by Filmation. Produced for syndication, the series quickly became a staple of saturday morning and weekday afternoon television. The series was marked by low budget and limited animation techniques involving heavily recycled animated sequences based on rotoscoped action. Despite this, the series was groundbreaking in terms of content for its time, breaking many taboos that had developed in children's entertainment that had prevented any level of violence or use of a television show to promote merchandising. In order to pacify critics of those contraversial elements, each episode would end with a moral that was explained to the audience by one of the protagonists, usually tied directly to the plot of the episode.
The series added and modified many elements compared to the previous comics. While King Randor and Queen Marlena were included in the comics, the animated series expanded their backstory, making Marlena an astronaut from Earth who was accidentally marooned on Eternia when her spacecraft crashed. Prince Adam and his pet green tiger Cringer both transform through the Power of Grayskull granted through a magic sword, becoming He-Man and Battle Cat. A bumbling magician named Orko was added for comic relief.
The series is notable now for the involvement of many famous creative minds including Babylon 5 creator J. Micheal Straczynski, Batman: The Animated Series writer Paul Dini, and Star Trek writer/editor D.C. Fontana.
The success of He-Man as a series led Mattel and Filmation to attempt to expand the Masters of the Universe franchise to be more female inclusive and market to young girls. He-Man had already drawn a surprising amount of female viewers, due partially to the writer's tendancy to create original female characters beyond those introduced in the toy line.
With this in mind Mattel introduced a line of toys under the banner Princess of Power, with She-Ra as its main protagonist, in 1985. The toys featured almost exclusively female characters with influence from popular fashion toys like Barbie incorporated into the figures. Instead of being created exclusively from molded plastic and rubber like Masters of the Universe toys, Princess of Power toys featured realistic hair and clothing. Filmation created a spin-off animated series title She-Ra Princess of Power based around these toys, setting it on the world of Etheria and featuring She-Ra as He-Man's long lost twin sister. The first episodes of the series were edited into a theatrical feature titled He-Man She-Ra The Secret of the Sword, and established She-Ra's (a.k.a. Princess Adora) backstory and her place as leader of the Freedom Fighters of Etheria. As the Princess of Power toy line only established one villain, Catra, the series had to adapt from the material they had. The characters of the Evil Horde, led by the Warlord Hordak, were initially created as Masters of the Universe figures but had not yet been incorporated into the animated series. As production on He-Man had stopped to focus on She-Ra, the Horde characters were adapted to become the main antagonists of She-Ra. Because of this, the premise of She-Ra was in many ways reversed from He-Man, as instead of defending a just world from evil invaders, She-Ra was fighting in rebellion of an evil establishment. Another crossover between the two series was produced in 1985, and released in December as He-Man She-Ra A Christmas Special.
Cannon films released a live-action film adaptation titled Masters of the Universe in 1987. The film starred Dolph Lundgren and Frank Langella. While often compared unfavorably to the animated series, it was made as an adaptation of the toy line only, and depicted He-man as a warrior with no alter-ego and Eternia as having no royal family with Castle Grayskul as the seat of power. Filmation had no involvement with the film whatsoever.
The plot revolved around Skeletor conquering Castle Grayskull using a device called the Cosmic Key. He-Man, Man-At-Arms, and Teela meet an inventor alien named Gwildor to challenge him, becoming stranded on Earth for a time while trying to recover their own Cosmic Key and retake the castle before Skeletor can claim the powers of the universe. The film focussed more on science fiction elements than most versions of the franchise, eliminating most references to magic. He-Man himself barely uses his sword, often uses laser guns, and only once performs any feat of super-strength. While Mattel hoped the film would revitalize the franchise, sales remained unaffected. That same year, Mattel stopped production on the Masters of the Universe toy line. A sequel film was written, but Cannon Films could no longer afford to pay the licence fees for use of the characters. Instead the costimes and sets were repurposed for the film Cyborg, a vehicle for Jean-Claude Van Damme. Some network television showings of the film have advertised the film as Masters of the Universe 2: Cyborg, leading to confusion among some that a sequel was made.
In 1989, Mattel attempted to relaunch the series, reaching out to DiC entertainment to produce a new animated series title The New Adventures of He-Man. This series differed in both animation quality and content from the Filmation series, shifting to an almost purely science fiction setting which sees He-Man transported to the futuristic planet of Primus ruled by Master Sebrian. As He-Man leads the Galactic Guardians, Skeletor bases himself on the evil world of Denebria, where he forms an alliance with Flogg and the Mutants, who are hellbent on conquering Primus for themselves. The series contains clear continuity links to the original Masters of the Universe, and was intended as a continuation of the existing mythology, although some fans see it as a separate canon from the original series due to the differences in style and character portrayal.
Other than He-Man and Skeletor, The Sorceress of Castle Grayskull is the only character from the original series to make regular appearances, acting as a guide to He-Man. Several other characters are featured in the pilot episode, including King Randor and Queen Marlena, who learn of the dual identity of Prince Adam and He-Man.
The majority of the cartoon episodes were written by Jack Olesker, resulting in a tight continuity, which was almost entirely lacking in the earlier Filmation series. Neither the New Adventures animated series or toyline were nearly as popular as the originals, lasting only sixty-five episodes and a few poorly received waves of action figures.
In 2002, Mattel launched a new Masters of the Universe toyline.. The new toyline was made surprisingly faithful to the original line, with the characters gently "re-imagined" and updated in terms of sculpting detail rather than radically reinterpreted.
One point of contention for many fans of the original Masters toyline was the redesign of He-Man's Power Sword. According to the design studio, Four Horsemen, this was due to their original re-sculpts being intended for a continuation of the original storyline in which Skeletor had obtained both halves of the Power Sword (hence the new Skeletor figure's dual blades with clear "good" and "evil" hilt designs), necessitating a new sword to be built by Man-At-Arms and endowed with the properties of the original by the Sorceress. However, Mattel decided to reboot the continuity for a new generation of children, and thus the "new" Power Sword design became the "original" version for the new continuity.
A new animated series was produced to accompany the toyline, made by Mike Young Productions and lasting for 39 episodes. This series involved much tighter continuity and a somewhat greater depth of characterization than its Filmation predecessor.
Later episodes of this series were retitled Masters of the Universe vs. the Snake-Men, and sidelined Skeletor as chief villain in favor of King Hiss, leader of the reptilian Snake Men. Hordak and The Evil Horde were to be the main antagonists for the third season if the show had continued.
Riffing group Ronin Fox Trax has released three riffs to date from the Masters of the Universe franchise, starting with the feature film version of He-Man She-Ra The Secret of the Sword in 2007, and He-Man She-Ra A Christmas Special and the live action Masters of the Universe film in 2009.