It’s a rare feat for a classical musician to become synonymous with a work that wasn’t commissioned for him or her. Pablo Casals’ name is nearly as associated with Bach’s glorious six suites for cello as the master Baroque composer himself. The future virtuoso and conductor found the score for these then-underappreciated and now-canonical etudes while perusing a shop in Barcelona with his father. “I was thirteen at the time, but for the following eighty years the wonder of my discovery has continued to grow on me,” Casals wrote in his autobiography. It would be 34 years before he would start his first and only recordings of these works.