Ballgown, early 1860s. From a past ebay auction (Time Travelers Antiques.) The seller said c. 1864, but I think that’s latest possible date. Ballgown styles don’t change too much until 1865-6 with the new straight waists, tiny sleeves, and elliptical skirts. This bodice with the deep pointed waist and very wide berthe could easily be from 1860. The combination of pink windowpane sheer silk with the band of printed silk is amazing. The berthe is trimmed with expensive bobbin lace.