According to her Wikipedia article, she was Holy Roman Empress from 1648 to when she died in childbirth in 1649 at the age of 17. She was the daughter of Claudia de Medici. Her maternal grandparents were Ferdinando I de' Medici, Grand Duke of Tuscany and his wife Princess Christina of Lorraine.
From history-of-fashion.tumblr.com/post/141359404634/1648-unknown-artist-portrait-of-maria-leopoldine; enlarged one quarter.
The Empress wears a saya, albeit with a basque bodice and puffed sleeves. A collar replaces the ruff, as seen in Velazquez portraits.
Keywords: 1648, Maria Leopoldine von Österreich-Tirol, Maria Leopoldine (1632-1649), römisch-deutsche Kaiserin, Habsburg family, Archduchess, Empress, proto-hurluberlu coiffure, bangs, earrings, necklace, basque bodice, hair jewelry, high neckline, lace collar, lace ruff, brooch, draped jeweled bodice ornament, hanging sleeves, lining, puffed paned over-sleeves, under-sleeves, bows, turned back cuffs, jeweled bodice ornament, over-skirt, full under-skirt, saya