The following story will explain why the Chevalerie du Fourquet des Brasseurs pays tribute to Gambrinus and why he is nearly always shown sitting astride a beer barrel. 

Gambrinus is a deformation of the name "Jan Primus", which is the Flemish name for Duke Jean I, the son of Henri III and Alix of Burgundy. Born in 1210, he inherited both the duchies of Brabant and Lorraine. He was famed for being a benefactor and a genuine hero. He also became a famous figure in the history of Belgian beer-making. 

He laid down the foundations for Brabant's brewing industry by allowing the deputy mayors of Brussels the right to grant licences for brewing and selling beer. He was also the honorary President of the Brussels Brewers' Guild. He was known for being very fond of a mug of beer. Legend has it that during a three-day banquet he drank mug after mug of foamy beer and he was known forever after as the King of Beer. 

One day, at the end of a fierce battle, Jan Primus invited all the noblemen to celebrate the victory. During the festivities, he went to an inner courtyard where his soldiers and servants were making merry. Determined to make a speech to these hearty fellows, he climbed on top of a pile of barrels and sat astride the highest one. With a foaming mug in one hand, he addressed the crowd by proposing a toast to his country and the health of his people. And this is how he became a legendary figure. 

Another of his enthusiasms was taking part in tournaments but this provided to be his undoing. He died in 1249 from wounds he received during a tournament in Bar-le-Duc. 

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