The six Cello Suites, BWV 1007-1012, are suites for unaccompanied cello by Johann Sebastian Bach. They are some of the most frequently performed and recognizable solo compositions ever written for cello. Bach most likely composed them during the period 1717–23, when he served as Kapellmeister in Köthen. The title given on the cover of the Anna Magdalena Bach manuscript was Suites à Violoncello Solo senza Basso (Suites for cello solo without bass). Due to the works' technical demands, étude-like nature, and difficulty in interpretation because of the non-annotated nature of the surviving copies, the cello suites were little known and rarely publicly performed until they were revived and recorded by Pablo Casals in the early 20th century. They have since been performed and recorded by many renowned cellists and have been transcribed for numerous other instruments; they are considered some of Bach's greatest musical achievements. Yo-Yo Ma performed the Bach Unaccompanied Cello Suites in its entirety – nearly three hours! – in London at The Proms concert to more than 5,000 people. And the reviews were fantastic: “Without doubt, we were in the presence of a great musician, and a great man. One to file in the concerts of a lifetime.”– BBC Music Magazine“ The cellist’s grand interpretation at Prom 68 would have left the composer astonished and incredulous.”– The Guardian Yo-Yo Ma won a Grammy Award for Best Instrumental Soloist Performance for his performance of The six Cello Suites in 1985.