 "Bartók's last two quartets proclaim the sanctity of life, progress and the victory of humanity despite the anti-humanistic dangers of the time", writes analyst John Herschel Baron.The last quartet, written when Bartók was preparing to flee the Nazi invasion of Hungary for a new and uncertain life in the U.S., is often seen as an autobiographical statement of the tragedy of his times.Bartók was not alone in his explorations of folk music.