Her Wikipedia article is here.
From Wikimedia; veiling reflection on right side suppressed with Photoshop by gogm.
Benigna wears an early 1700s dress with a criss-cross bodice and notched sleeves and a red order sash reflecting her role as Lady-in-Waiting to the Duchess of Courland, Anna, who became Tsaritsa in 1730.
Keywords: 1730, Lippold, Benigna Von Biron, von Trotta Truiden family, Courland family, Duchess, Russian, Lady-in-Waiting, Anna Ivanova, long straight coiffure, hair jewelry, trapezoidal neckline, modesty piece, corset, criss-cross bodice, elbow length close notched sleeves, order sash, order star, Sévigné bodice ornament, clasps, robes