From the Publisher's site:
The Stupor Mundi RPG was born years ago, when your Webmaster and Gamemaster Rosen McStern got tired of the usual roleplaying settings with muscular barbarians who speak dozens of languages and magicians who know everything but have never left their towers. Having read an old book about the Swabian dynasty of the Hohenstaufen, he converted his beloved RuneQuest campaign into a historically accurate game based upon a 13th century Europe where magic really works and astrologers can tell a man's ultimate destiny.
Many years after that moment, thanks to Issaries Inc., the new owner of the RuneQuest Trademark, and to the Open Gaming license policy that Mongoose Publishing, the new publisher of RuneQuest, has adopted, Stupor Mundi is no longer just a house campaign but a new, complete setting for RuneQuest!