In a productive career lasting only eight years, Klein, who died young at the age of 34, made a name for himself with his monochromatic pictorial compositions executed in an ultramarine that he developed himself and patented under the name “International Klein Blue”. Cofounder of the artistic movement known as Nouveau Réalisme in France, the artist later incorporated products of nature into his works, like the sponges painted a single shade, and thus expressed a new sensitivity toward materials and colours. The subtitle originates with the artist, who listened to Mozart’s Eine Kleine Nachtmusik while making the work.