Richmond Cotillion performed on banjo and mandolin. In my own research, I have learned that a Cotillion is not so much a type of dance but a format in which dancers must continually swap partners. Likewise, the reel form we refer to today as a cotillion, changes keys between the A and B parts. This modulation provides an unmistakable signal that it's time for the dancers to switch. This oldtime tune is also known as the Green Mountain Polka and Old Richmond.