Teresa Kunegunda Sobieska, Electress of Bavaria by ? (auctioned by Sotheby's)
From Wikimedia; lower corners fixed with Photoshop by gogm.
Theresa Sobieska wears a dress with an off shoulder scoop neckline with the modesty piece spilling out over it and puffed sleeves decorated with a single back- and single forward-flared engageantes in 1600s style. The slashed sleeves may be a theatrical flashback.
Keywords: Theresa Kunegunda Sobieska, Sobieski family, Wittlesbach family, Princess, long curly coiffure, off shoulder scoop neckline, modesty piece, lace, elbow length puffed sleeves, slashed sleeves, forward-back flared engageantes, necklace, earrings, clasps, robes