From the very beginnings of polyphony, dance music was performed by professional minstrels; it was part of popular music, and no one seems to have thought to put it on the same footing as the learned music—either sacred or profane—that was played in the churches and courts. The social circles in which these two styles were played rarely came into contact and, furthermore, ecclesiastical authorities disapproved of the lowly peasant dances. However, it was inevitable that the two would eventually cross paths, and ancient traditional dances began to be performed in brilliant multi-voice renditions.
Unfortunately, not much is known about dance music of this era, as it was simply passed down in an oral tradition, from one generation of minstrels to another—doubtless with variations and modifications according to current styles. Very early on, the dances were divided into two parts; the first in duple meter and danced with walking and gliding steps, and the second being a variation of the first, was either at double the speed or in triple time and danced with skips and jumps.
With that in mind, one has to wonder if the doubles in this partita are Bach's way of paying homage to that ancient tradition.