The Bach collection of six suites for solo cello may have been written around 1720 as basic practice pieces intended to help hone a player’s technique. When examined by order of their numbering, the suites reveal a progression from relatively straightforward to highly complex all of which implies their skill-training nature.
The original autograph of Bach's Cello Suites were never found, so its only source is a copy made by his wife Anna Magdalena. The copies, however, didn't contain any of the articulations or intended dynamics, hence there is no definitive interpretation of the works and so performances vary quite a bit.
The cello suites were also transcribed for guitar, trumpet, and other instruments.
Andres Segovia plays his fantastic transcription of the prelude to the Cello Suite No.1 in G:
After Bach’s death, his suites were forgotten by the general public, and remained largely unknown until their discovery at a secondhand book store by virtuoso Pablo Casals at the age of 13. Throughout the years, Casals worked on his playing technique to bring them back to life which he finally achieved with his 1930s performances and recordings.
Here is Jacqueline du Pré plays Cello Suite No.1 in G: