Who is XXX's sister?
Ulla von Höpken
She is also famous in history as one of ``the three graces'' of the Gustavian age; three ladies-in-waiting (Augusta von Fersen, Ulla von Höpken and Louise Meijerfeldt) immortalized in the poem Gracernas döpelse by Johan Henric Kellgren, and known profiles of the epoch.
Augusta von Fersen