This rare portrait of Bach, by Elias Gottlob Haussmann, hung in John Eliot Gardiner's home during World War II. courtesy of William H. Scheide, Princeton, N.J. hide caption

itoggle caption courtesy of William H. Scheide, Princeton, N.J.

An autographed portrait of Ludwig van Beethoven. Hulton Archive/Getty Images hide caption

itoggle caption Hulton Archive/Getty Images

John Eliot Gardiner leads the Orchestre Revolutionnaire et Romantique and the Monteverdi Choir at Carnegie Hall in New York, NY on November 17, 2012. Melanie Burford for NPR hide caption

itoggle caption Melanie Burford for NPR

Conductor John Eliot Gardiner has strong opinions about Beethoven. /Chris Christodoulou hide caption

itoggle caption /Chris Christodoulou

Composer Jennifer Higdon wonders what Beethoven would think of cell phones and Thai food. J.D. Scott hide caption

itoggle caption J.D. Scott