This painting portrays the Infanta Margaret of Austria.
She was the daughter of King Philip the Fourth and Mariana of Austria.
In this portrait, the Infanta Margaret was already engaged to Emperor Leopold of Austria.
The wedding happened a year later.
Juan Bautista Martínez del Mazo painted the Infanta with features typical of the Habsburg family, such as light skin, blonde hair, large eyes and pronounced mouth shape.
The Infanta wears a silver-grey dress called a basquiña.
Basquiña means an outer skirt.
The dress is big because of a special frame under it.
This frame was called the pannier.
A large red curtain serves as a decorative background.
The portrait of the Infanta is very similar to portraits of her sister, the Infanta Mary Theresa, and her mother, Mariana of Austria, painted by Velázquez.
Four years before painting this portrait, Martínez del Mazo was appointed the chamber painter to King Philip the Fourth.
This job was the most prestigious position for a painter at that time.
Velázquez also held the same position until he died in 1660.