The Messiah Violin is supposed to be the most valuable in the world, but its authenticity has been called into question using both paper trails and a 1998 analysis, initiated by Stewart Pollens and carried out by Peter Klein, of closeup photos of the tree rings, which suggested the tree was cut down after Antonio Stradivari died. A microscopic study by John Topham and Derek McCormick in 2000 compared the instrument to other verified Stradivari and found it was from the right time period. Now a second study, led by Henri Grissino-Mayer, who stepped into the rather heated controversy last year, verifies that work.