Based,like many French or American movies of today on a comic strip;I have never read it ,but the movie belongs to another era :the late fifties and the early sixties .
All the cardboard characters we have seen a hundred times or more, are present: the dashing handsome prince ,the gorgeous (good) princess,the bad sadistic woman (a touch of racism here maybe) ,the poor people overburden with taxes (scenes taken by force from Robin Hood),the traitor,the would be comic relief provided by a giant named Goliath,always stuffing himself with food,his sidekick ,a midget;and to top it all, right in the middle of the crusades, help is on the way in the shape of a Muslim!Maybe words of wisdom for our troubled times ! The movie begins with historic pretensions ,but quickly opts for a poor man's heroic fantasy;there are as many plot holes as in Swiss cheese and,after this far-fetched tale, we can only be satisfied that the holy Grail is left in good hands.
As the prince swears to his mentor he 'll always side with the underdog ,they might make a sequel.