Matisse, like Picasso, was a giant of 20th century art, and career spanned the entire century.
The cut-outs, of which Nu Bleu IV is a part of, are some of Matisse's most popular works.
At 83, Matisse was inventing an entirely new art form.
Matisse had burst onto the scene at the beginning of the century, in 1904, with Fauvism.
He continued to create tirelessly throughout his life.
When the Germans invaded in 1940, he chose to remain in France.
He lived in Nice and, when it was bombed, moved to the small hilltop village of Vence, where he filled his house with paintings.
He developed a stomach cancer and could no longer paint.
So he had assistants pre-paint paper which he cut and paste, and assembled into sculpture-like figures.
Some of his cut-outs were so large they were turned into murals.