From Wikimedia; removed monocolor tint. Also posted to Agnes von Anhalt-Dessau’s new Subalbum here.
The skirt is a half dome and the sleeves are full suggesting the early 1860s.
Keywords: Agnes von Anhalt-Dessau, Friederike Amalie Agnes von Anhalt-Dessau, Prinzessin von Anhalt-Dessau, Herzogin von Sachsen-Altenburg, Princess Agnes of Anhalt-Dessau, Ascania family, Wettin family, Princess, Duchess, German, straight coiffure, floral headdress, earrings, necklace, fitted bodice, off shoulder vee neckline, elbow length full sleeves, contrasting cuffs, ruffled cuffs, bracelets, crinoline