Frederick II, Holy Roman Emperor and King of Germany and Italy, was a man of extraordinary culture, energy, and ability. His contemporaries called him "stupor mundi" ("the wonder of the world"), and many historians consider him Europe's first modern ruler. The kingdom Frederick established in Sicily and southern Italy ran on an efficient bureaucracy similar to modern, centrally governed kingdoms.

As one of Frederick II's vassals in Stupor Mundi, you will summon allies from around the Mediterranean, build structures in your castle, and promote specialists to improve your kingdom. You may improve your chances by upgrading your castles: towers house additional allies, walls store more resources, and keeps aid in managing action cards. Through a clever card-selection mechanism, you will have to choose actions carefully, some of which will trigger edicts that affect Frederick's palace, and determine the rewards players may receive from their allies. Do you stay loyal to the Emperor, or do you support independent allies? Keep a close eye on what your opponents do and form alliances at the right time — or go your own way when things get too heated...