It was always my understanding that the tune was written to commemorate Jackson's victory over the British, and was a popular dance tune for many years, as January 8 was actually celebrated as a holiday in many parts of the country. (I think we should revive that tradition, but that's another story.)

In regard to one of the other threads mentioned above, I thought it was Soldier's Joy that had been called The King's Head. (Whether the king's head was attached to his body at the time is anyone's guess.)