Frederick Adolf was not met with open opposition by his family, but his mother, the Queen dowager, and his brother the King were, in fact, opposed to it.

Her father stated in his papers that the reason for this suggestion was to "abuse the youth and lack of experience of my daughter and, if they could, make her the official mistress of the Duke", and he therefore declined the position of lady in waiting for Sophie.

[3] When Frederick Adolf continued to be in love with Sophie von Fersen after two years had passed, he and his brother Duke Charles proposed to Sophie von Fersen that they would abduct her from a ball of the duchess Charlotte and bring her to Prince Frederick's residence Tullgarn Palace, where a priest would be waiting to perform the ceremony before it could be prevented.

When Frederick Adolf tried to convince her to change her mind, she was almost ready to do so, but asked duchess Charlotte to take her to another room, so that her feelings would not persuade her to accept.

Sophie Piper is known for her intimate friendship to Hedvig Elisabeth Charlotte of Holstein-Gottorp, the spouse of Charles XIII of Sweden.

After her affair with Frederick Adolf, Sophie fell in love with the Russian Prince Alexander Kurakin, whom Empress Catherine the Great had sent to Stockholm in 1776 at the head of a diplomatic delegation.

[6] In 1779, she had a relationship with the Spanish envoy marquess Liano y las Qanchas, who at one point lived at Ängsö Castle with her and her spouse, and later with the French envoy count Louis Claude Bigot de Saint-Croix, whom she shared with Eva Löwen, while her spouse was in turn the lover of Ulla von Höpken.

[7] Sophie Piper is known to be one of five women to have been a member of the Freemasons in Sweden during the 18th century: alongside Hedvig Eleonora von Fersen, Countess Ulrica Catharina Brahe and (not as surely documented but most likely) Christina Charlotta Stjerneld, she is confirmed as a member of a Freemasonic adoption lodge for women at court in 1776, when Princess Hedvig Elisabeth Charlotte was initiated by her consort Duke Charles as Grand Mistress of the female lodge.

In their correspondence, Sophie reproached Axel for his sexual relationship to Eleanore Sullivan out of consideration for the feelings of Marie Antoinette: "I truly hope that she will never find out about this, for it would give her great pain", and: "Think of Her, the poor one, spare her such mortal sorrows!

After the deposition of Gustav IV Adolf of Sweden in 1809, the Fersen siblings were known supporters of the Gustavian Party, who wished for the son of the deposed monarch to be acknowledged as heir to the throne.

Like her brother Axel, Sophie fell under false and unfounded suspicion of involvement in crown prince Karl August's death in 1810.

She was warned that she would be forced to share his fate, and she therefore left Stockholm the same night disguised as a maid and sought refuge at Rydboholm Castle.