in
Stettin, now in
Poland The marriage of Joanna and Christian August turned out to be a mismatch because of their large age gap and different personalities. On 22 January 1729, after Christian August was appointed commander of Stettin, the couple moved into the castle in the middle of the city. Joanna, who remained dissatisfied with her position and her social isolation, started travelling to escape Stettin. She often visited Brünswick, her childhood home, and every February during the carnival season she paid her respects to the
King of Prussia. Much to her dismay, she was treated as a poor relative and pitied for her marriage to someone below her in rank. On 21 April 1729, Joanna gave birth to her first child, Sophie Auguste Friederike. Everyone had hoped for a son and heir to his father. As compensation for having to marry a minor prince, Joanna wanted to raise a great ruler. To her great disappointment, the baby was a girl. on 8 August 1734, to
Frederick Augustus, who would succeed his father as Prince of Anhalt-Zerbst; and on 10 November 1736, to Auguste Charlotte Christine, who died two weeks later. Joanna's relationship with her eldest child remained strained. According to Sophie's memoirs, Joanna was often violent and angry towards her for no reason. In 1741,
Grand Duchess Elizabeth Petrovna of Russia ascended to the throne as empress. She had once been engaged to Joanna's brother Charles Augustus (1706–1727), who died shortly before the wedding, and she cherished his memory for her whole life. Joanna was quick to write a congratulatory letter, and later sent a portrait of Elizabeth's deceased sister,
Grand Duchess Anna Petrovna, and received a valuable portrait of the Empress in return. To further the relationship, Joanna sent a portrait of Sophie to the Empress, who was pleased with her beauty.
In Russia On 1 January 1744, Joanna was handed a letter from
Otto Brümmer, the Grand Marshal of
Grand Duke Peter's court. (Peter Ulrich had converted to
Russian Orthodoxy and had taken the name Pyotr Fyodorovich.) In the letter, Brümmer asked Joanna to come to Russia with her eldest daughter as soon as possible on the command of the Empress. Only a few hours later, a letter from
Frederick II of Prussia arrived to inform Joanna that Frederick saw a possibility to arrange a marriage between Peter and Sophie. There the King secretly asked Joanna to become an agent of Prussia in
Saint Petersburg in place of Vice Chancellor Count
Alexey Bestuzhev-Ryumin (1693–1768), an enemy of Prussia who wanted Russia to be allied with Austria and opposed the marriage of Peter and Sophie. Joanna enthusiastically accepted. On 16 January, after the family and their company left Berlin, Christian August said goodbye and returned to Zerbst, as the Empress had asked him not to go to Russia. At first, Joanna had a cordial relationship with Empress Elizabeth, often expressing gratitude for her kindness towards her family. However, when Sophie fell ill and the doctors wanted to
bleed her, Joanna refused to allow it. That angered the Empress, who removed Joanna from her daughter's bed and tended to Sophie herself. Joanna's constant complaining during this period caused the Russian court to dislike her. While in Russia, Joanna was working on the mission she had received from the King of Prussia, trying to undermine Vice Chancellor Bestuzhev. After Bestuzhev intercepted letters between Joanna, the Prussian and the French ambassador, and the Prussian and French courts, he eventually presented copies to the Empress, who was furious and declared that Joanna must leave Russia right after the wedding. Between the betrothal and the wedding, Joanna's relationship with her future son-in-law also deteriorated. After Peter and Sophie were married on 21 August 1745 (O.S.), Joanna left Russia without saying goodbye to Sophie (now known as Grand Duchess Catherine Alexeievna), whom she would never see again. Although Joanna departed with many presents from the Empress, in Riga, she was directed to take a message to the King of Prussia, asking him to call back the ambassador who had been caught in the conspiracy against Bestuzhev. This request was a humiliating punishment for Joanna's part in the plot. ==Regency and later life==