The bbc.co Web site dates this "1715/1725." She is said to be born either 1656 or 1659. A 1715 completion date would make the sitter 56 years old if she was born in 1659. This is a well-preserved 56-year old person. The 1725 completion date is preposterous unless this is based on an earlier portrait of her or the portrait is of another person.