Edmund Berkeley’s 1718 inventory included portraits of himself and his lady. His first wife was Mary Mason and his second wife was Lucy Burwell. Either woman could be the subject of the painting, but it seems more likely to have represented Lucy Burwell Berkeley.
Reference: 1718 Inventory of Barn Elms, “Home House Plantation,” includes, “his own and Ladies pictures, Eleven house pictures, King William & Queen Mary, smal”
See: “Virginia Council Journals,” Virginia Magazine of History and Biography, 35, 1 (January 1927), 37.