According to her Wikipedia article, "Katherine Stanhope, Countess of Chesterfield (1609–1667) was the governess and confidante of Mary, Princess Royal and Princess of Orange."
Sir Anthonis van Dyck passed in 1641.
Katherine Stanhope is well, but not lavishly, dressed for her van Dyck portrait. Her dress has a trapezoidal neckline with a modesty piece barely visible in this image.
Keywords: van Dyck, Katherine Stanhope, Countess of Chesterfield, Wotton family, Stanhope family, Stuart family, Lady-in-Waiting, Princess Royal Mary Stuart, Anne Hyde, Catherine of Bragança, curly coiffure, jeweled hat, trapezoidal neckline, modesty piece, puffed sleeves, slashed sleeves, fur, necklace