She married August of Saxony in 1612 and then Johann Philipp of Saxe Altenberg in 1618. Her article in thepeerage.com is here.
From Wikimedia.
Elisabeth’s dress is very close to English styles with a wheel farthingale. She wears two different colors of pearls while her skirt is adorned with seed pearls. She wears a large brooch on the side of her coiffure to her left.
Keywords: 1609, van Doort, Elisabeth von Braunschweig-Wolfenbüttel (1593–1650), Prinzessin von Braunschweig-Wolfenbüttel, Herzogin von Sachsen-Altenburg, Elisabeth of Brunswick-Wolfenbüttel, Duchess of Saxe-Altenburg, princess of Brunswick-Wolfenbüttel, Duchess of Saxe-Altenburg, Braunschweig-Wolfenbüttel family, Wettin family, Princess, Duchess, German, high straight coiffure, hair jewelry, earrings, necklace, draped necklace, fitted bodice, vee neckline, lace neckline ruff, long close sleeves, lace back-flared cuffs, brooch, girdle, deep vee waistline, wheel farthingale, jeweled skirt