Exert from the National Gallery website

“A young woman floats above a landscape, standing on a translucent moon and with a crown of 12 stars. This imagery is based on the New Testament Book of Revelation. In it, Saint John the Evangelist records his vision of the Woman of the Apocalypse, who bears a male child and is threatened by a dragon – the devil.

In the Catholic faith, this woman represents the Virgin Mary, the mother of Jesus Christ. Her hands are clasped in prayer and she looks down in humility to show her protection over mankind. The garden, fountain, temple and ship at the bottom are all symbols normally associated with her and were included in a litany (or prayer) dedicated to the Virgin.

With its companion painting, Saint John on the Island of Patmos, this is one of Velázquez’s earliest known works.”