From the Tate Collection's Web site.
Lady Spencer's dress is almost a replica of this dress worn by Queen Henrietta Maria in the same time period.
Keywords: van Dyck, British, Spencer family, British, curly coiffure, jeweled ribboned headdress, square neckline, lace collar, rosettes, jacket bodice, lace bertha, bows, elbow length puffed sleeves, lace cuffs, waist band, natural waistline, full skirt, necklace, earrings, bracelets