The boy is probably Felix, later the assassin of Grigori Rasputin.
Zinaida dresses in a late 1880s bodice, recognizable by the up turned sleeves, made of soft material over a silky chemisette.
Keywords: Zinaida Yussupova (1861-1939), Zinaida Yusupova (1861-1939), Зинаи́да Никола́евна Юсу́пова, Princess Yussupov, Yussupov family, Sumarokov-Elston family, Princess, Countess, Russian, straight coiffure, braided bun, earrings, chemisette, high enclosing neckline, draped bodice, vee décolletage, pin, long close sleeves, contrasting cuffs