Her Wikipedia article is here. She was the fourth of Barbara Palmer's children. The name FitzRoy means "King's son." She had 18 children, the first being Charlotte Lee, Lady Baltimore, first married to Benedict Calvert, 4th Baron Baltimore. Baron Baltimore struggled with the title to the family's property in North America, the colony of Maryland.
From bbc.co.
Charlotte Fitzroy is shown wearing a modest dress, by Kneller standards, and a veil. The dress is typical Kneller with split bodice, puffed sleeves, and a wrap. The shadows may conceal fripon forehead curls dating this to 1700 ±15 about years.
Keywords: Kneller, Charlotte FitzRoy, Charlotte Lee, Countess of Lichfield, Stuart family, Lee family, Countess, straight coiffure, veil, chemise, modesty piece, vee neckline, puffed sleeves, split bodice, split bodice, quarter length notched over-sleeves, clasps, wrap