The great Johann Sebastian Bach had died 30 years earlier. But at that point, nobody really knew his work. It hadn't been published, and the only people who had it were devotees who passed around hand-written copies. One of those devotees was the Baron von Swieten, in Vienna. The Baron had a young friend named Mozart, and every Sunday, Mozart would go see the Baron, and play Bach. Mozart was enthralled. He copied out the music, studied what Bach had written for the keyboard, and re-arranged it for string quartet. On Wednesday's Performance Today, we'll hear the Orion Quartet play fugues by Bach, lovingly re-imagined by Mozart.