Before Bach, the keyboard was primarily used to provide a harmonic shape to a piece. It was stuck in the back - out of the way - and mainly kept time and colored the lines.
There was no such thing as a 'keyboard concerto' until one of the finest virtuosos on the instrument came along - Johann Sebastian Bach.
Bach placed his keyboard front and center -- at least musically -- by allowing it to be the solo instrument.
And what a revolution that was.
In the case of the so-called Brandenburg Concertos, especially No. 5, the most shocking thing of all is that the harpsichord starts out in his old job -- keeping time and shaping the harmony while the flute and violin shine.
Then suddenly, about two-thirds of the way into the first movement -- just when you were sure the piece was winding down -- everything comes to a screeching halt and the harpsichord takes over.
It's as though the harpsichordist, most likely Bach himself back in the day, had finally gotten fed up in his role in "the chorus" and finally wanted his chance to shine.
He pushes everyone aside and plays alone for about five minutes or so in a kind of free-form style, venturing into some wild places and keys.
It's pure magic.
The keyboard concerto was never the same after Bach's Brandenburg No. 5.
This is a performance from last December with members of the Saint Paul Chamber Orchestra and Skip Layton James at one of his own hand-built harpsichords.