The Belgian Dubbel style has technically been around since the Middle Ages, but as Kegworks Blog points out, the current style began growing in popularity more in the mid-19th century:
Although Belgian Dubbel originated at monasteries in the Middle Ages, we have the Trappist Abbey of Westmalle to thank for providing it to the masses. 1856 was the year it was in its infant stage, when the abbey had been brewing a sweeter, lower alcohol Witbier that served the purpose as a table beer for the monks since 1836. Dubbel was designed as a stronger version of a brown ale, with the first official sale of the beer taking place in 1861, and in 1926 it was "reformulated" again to be even more potent.The Dubbel gets its name because the style is brewed with double the amount of malt than a typical beer style. Of course, with the extra malt comes a higher alcohol content, so it is a nice rich, dark amber beer that can be enjoyed while relaxing in front of a fire, or hanging with friends at our Old Plant No. 1 Pub location.
We'll keep you posted when we have a more definite date for its debut. Cheers!