How did Picasso think of it? There was an interesting story behind (here is an excerpt of Brassaĩ’s book “Conversations with Picasso”) :
“Once a woman enters with a package carefully tied up with string under her arm. She would like to see Picasso “in person”. She has something to show him that will undoubtedly interest him. She can wait for him all morning if necessary. When Picasso returns two hours later, she undoes the package and takes out a little picture: “M. Picasso,” she says, “allow me to present you with one of your old paintings.” And he, always rather moved to see again a work long lost from sight, looks tenderly at this little canvas.
Picasso: Yes, it’s a Picasso. It’s authentic. I painted it in Hyères where I spent the summer in 1922.
The Visitor: May I ask you to sign it, then? Owning a real Picasso without his signature is very distressing, after all! People who see it in our home may assume it’s a fake.
Picasso: People are always asking me to sign my old canvases. It’s ridiculous! In one way or another, I always marked my pictures. But there were times when I put my signature on the back of the canvas. All my works from the cubist period, until about 1914, have my name and the date on the back side of the stretcher. I know someone spread the story that in Céret, Braque and I decided not to sign our pictures anymore. But that’s just a legend! We didn’t want to sign the painting itself, that would have interfered with the composition. And even later, for that reason or for another, I sometimes marked my canvases on the back. If you don’t see my signature and the date, madam, it’s because the frame is hiding it.
The Visitor: But since the picture is by you, M. Picasso, couldn’t you do me the favor of signing it?
Picasso: No, ma’am! If I were to sign it now, I’d be committing forgery. I’d be putting my 1943 signature on a canvas painted in 1922. No, I cannot sign it, madam, I’m sorry.”