The way the artist had worked out how to position the various elements in the painting suggested da Vinci's way of working.

CNN: Decoding da Vinci: How a lost Leonardo was found

Art history is often presented with various kinds of puzzles, including how to reconcile what an artist has said about a work when its visual evidence suggests the opposite.

WSJ: Vanitas I | Georges Braque | Denying Death | Masterpiece by E.A. Carmean Jr.

Even as the artist behind it remained unknown, the BNE logo in its various forms became one of the most recognizable brands worldwide.

FORBES: Rebel With a Cause: An Interview with BNE

Whoever the sitter is, this painting offers a rare glimpse of the artist working out his thoughts in paint, showing in a single canvas the various stages of creating a picture.

ECONOMIST: Portrait of a lady and her daughter

The various tercentenary exhibitions this year provide the ideal opportunity for a long-overdue reassessment of this by no means insignificant artist.

ECONOMIST: Il Cavaliere Calabrese