This piece by JS Bach
Performed by Jean Rondeau
[For this work] we have to thank the instigation of the former Russian ambassador to the electoral court of Saxony, Count Kaiserling, who often stopped in Leipzig and brought there with him the aforementioned Goldberg, in order to have him given musical instruction by Bach. The Count was often ill and had sleepless nights. At such times, Goldberg, who lived in his house, had to spend the night in an antechamber, so as to play for him during his insomnia. … Once the Count mentioned in Bach’s presence that he would like to have some clavier pieces for Goldberg, which should be of such a smooth and somewhat lively character that he might be a little cheered up by them in his sleepless nights. Bach thought himself best able to fulfill this wish by means of Variations, the writing of which he had until then considered an ungrateful task on account of the repeatedly similar harmonic foundation. But since at this time all his works were already models of art, such also these variations became under his hand. Yet he produced only a single work of this kind. Thereafter the Count always called them his variations. He never tired of them, and for a long time sleepless nights meant: ‘Dear Goldberg, do play me one of my variations.’ Bach was perhaps never so rewarded for one of his works as for this. The Count presented him with a golden goblet filled with 100 louis-d’or. Nevertheless, even had the gift been a thousand times larger, their artistic value would not yet have been paid for.
The piece is an hour and a half long and I don’t know if it was performed in one setting, if so I hope the performer iced his hands down afterward, a lot of key strokes there.