Bill Monroe’s Gibson F-5 Master Model mandolin—one of the most renowned and celebrated instruments in the history of bluegrass and country music—turns 100 years old today, July 9. When Monroe, now a member of the Country Music Hall of Fame and widely known as the Father of Bluegrass, purchased the instrument, it was used and already about twenty years old. He was in Florida in the early 1940s when he spotted it in a barbershop window next to a “For Sale” sign. He bought the mandolin on the spot,