Have you seen this painting before? It's by Bronzino and the subject is Bia, the almost 6-year old illegitimate daughter of Cosimo de Medici. He was just 16 when Bia was born and once he married and had kids, she grew up alongside her half-siblings.
I love this portrait, and knowing Bia was already dead when it was painted makes it even more emotional to me. The utter despair of losing a child. I can sense the immediate need of having her picture painted soon, soon, to have her likeness around.