In 2001 Joe and his, wife Helen Hayes, then the president of the VSA made a trip to the Ashmolean Museum in Oxford to study the Stradivarius' Messiah. The authenticity of this famous violin had been questioned; three American dendrochronologists had been asked to examine the instrument and to determine the age of the spruce top. This panel of experts spent several days examining the Messiah and several instruments known to have been made by Stradivari and other Cremonese makers. The violin, made in 1716 by Stradivari is thought to be the only Stradivarius that still remains in a 'new' state, as it was seldom played and has been preserved through time with much care and protection. It was donated to the British nation with the proviso that it never is played again.
You can read the full publication from the Violin Society of America that goes in depth into the journey here as pdf.
Below are also some of the photographs from the trip and of the Messiah up close.