This is a painting by Gerard Honthorst from 1652. If features the pronounced light and dark effect seen that was his trademark. The subjects of the portrait are Mary Stuart, Princess of Orange and her son William III.
Mary married William II of Orange-Nassau at the age of nine. He is not in the painting, as he died before the birth of his son.
Mary and her son were often at Breda Castle. The orange tree in the foreground, bearing the ‘apples of Orange’ as they are known, is the symbol of the family in the painting.
Portrait of Mary Henrietta Stuart and her son William III, Gerard van Honthorst, 1652, oil on canvas | Stedelijk Museum Breda; on loan from Breda council