The Hungarian bandit comes up with the idea to propose a partnership to a cadet nobleman, so the group can take possession of the aforementioned fief and enjoy its riches.

Brancaleone initially refuses the plan but after a farcical defeat at a jousting tournament that promised the hand of an overlord's daughter and a wealthy fief, he is too eager to take command of this "army" (L'Armata) of underdogs and lead it towards "fortune" and "glory", in what he sees as an epic journey.

As they set up towards the fief, Brancaleone lives several grotesque adventures, inspired by the confused and cosmopolitan world of Italy during Middle Ages; each one of them more hilarious than the last.

Age and Scarpelli devised for the characters a striking, mocking form of a mixture of Italian (including its dialects) and Latin languages, which is probably the main feature of the film and one of the keys to its success.

According to Monicelli, the idea for the movie was spurred by a simple scene written by Age and Scarpelli, about two mediaeval peasants talking about women.

There is no such stereotype left standing: the oppressed villagers are capable of violence themselves (they are prey to the bandits, but join them to attack their saving knight); the clergy, depicted by the hallucinating monk, fanatical to the extreme, always capable of explaining misfortunes by "lack of faith" of his entourage; the miserly Jewish merchant; the heroine/princess in distress, who instead of ending up with the hero asks to be deflowered by another man just to spite him.

Finally, the archetypical medieval hero, the knight, has in the clueless Brancaleone its greatest parody, always jeopardized by following his chivalric code of conduct; as for his dreams of glory, he leads an army of underdogs that are a little more than a band of cowardly bandits who flee from fights and feign submission while actively trying to manipulate him from the bottom.