Finding genealogical information about her was difficult. She was born in 1864, making her a 16 year-old teenager. She died in 1883, never passing her teenage years. A genealogical sketch for her is here, but the linked Web site may demand joining the service.
From Pinterest search.
Teenage Isabella Potocka looks mature in this striking dress and jacket ensemble with a neckline emphasized with white ruffles.
Keywords: 1880, Makart, Isabella Potoka, Countess Potocka, Potocki family, Potochwski Sanguzco family, Countess, curly coiffure, chemise, pleated collar, ruffled modesty piece, square décolletage, cuirasse bodice, buttons, jacket, floral jacket ornament, elbow length close sleeves, back-flared cuffs, flared lace cuffs, close skirt, fan