1911 Encyclopædia Britannica/Gambrinus

GAMBRINUS, a mythical Flemish king who is credited with the first brewing of beer. His name is usually derived from that of Jan Primus, i.e. Jan (John) I., the victorious duke of Brabant, from 1261 to 1294, who was president of the Brussels gild of brewers; his portrait with a foaming glass of ale in his hand had the place of honour in the gild-hall, and this led in time, it is suggested, to the myth of the beer-king who is usually represented outside a barrel with a tankard in his hand.