I cannot find anything out about Christiana Eulenau besides this portrait. More information about it can be found here.
From oldrags.tumblr.com/tagged/16th+century/page/2.
This dress with its probable lily-shaped skirt, laced waist band, and segmanted and slashed sleeves is very German. Fashion is not homogeneous.
Keywords: 1534, Cranach - Lucas the Elder, Christiana Eulenau, Christiane Eulenau, jeweled coif, jeweled feathered hat, neck band, jeweled neck band, necklace, over-bodice, collar, piping, long tight virago sleeves, slashed arm bands, cuufs, rings, partlet, under-collar, square décolletage, jeweled bodice ornaments, under-bodice, square neckline, lace waist band, matural waistline, close skirt, skirt ornament