When I began writing the Conan stories a few years ago, I prepared this "history" of his age and the peoples of that age, in order to lend him and his sagas a greater aspect of realness. And I found that by adhering to the "facts" and spirit of that history, in writing the stories, it was easier to visualize (and therefore to present) him as a real flesh-and-blood character rather than a ready-made product. In writing about him and his adventures in the various kingdoms of his Age, I have never violated the "facts" or spirit of the "history" here set down, but have followed the lines of that history as closely as the writer of actual historical-fiction follows the lines of actual history. I have used this "history" as a guide in all the stories in this series that I have written.
— Robert E. Howard, "The Hyborian Age"
Now I held in my hands a vast methodical fragment of an unknown planets entire history, with its architecture and its playing cards, with the dread of its mythologies and the murmur of its languages, with its emperors and its seas, with its minerals and its birds and its fish, with its algebra and its fire, with its theological and metaphysical controversy. And all of it articulated, coherent, with no visible doctrinal intent or tone of parody.
[Jim Henson] had fallen in love with the [feature film] process for multiple reasons. For one, Jim's fascination with world-building was satisfied with the lengthy pre-production phase of the feature film cycle. Getting to truly develop a world down to its details and then construct it for the screen was a dream for his creative mind. Also, being a feature film director was a status symbol in the industry, and Jim seemed to want to be regarded in the same way that a creator like George Lucas was. Those were the upsides, but now, after the film's failure, he was experiencing the downsides. World-building is fun, but when an audience rejects the world that a creator imagines, the work seems to have been in vain. With feature films, that is a gamble, and with Labyrinth, it was an expensive, time-consuming gamble that didn't pay off.