|Birth||November 24, 1685 (Augustenborg)|
|Death||December 25, 1761 (Stävlö Castle)|
Dorothea of Schleswig-Holstein-Sonderburg-Beck, known also as Dorothea von Holstein-Beck and Dorothea von Ziedewitz, (24 November 1685 – 25 December 1761), was a German princess of the House of Oldenburg and by marriage Margravine of Brandenburg-Bayreuth-Kulmbach.
She was the eldest of the thirteen children of Frederick Louis, Duke of Schleswig-Holstein-Sonderburg-Beck, by his wife, Luise Charlotte of Schleswig-Holstein-Sonderburg-Augustenburg. Of all her siblings, only seven survived adulthood: Frederick William II, who inherited Beck after succeeding his father; Charles Louis, later husband of the Countess Orzelska and ruler of Beck after the death of his nephew; Philipp Wilhelm, who died unmarried in 1729; Luise Albertine, by marriage von Seeguth-Stanislawsky; Peter August, who years later inherited Beck from his older brother; Sophie Henriette, Burgravine and Countess of Dohna-Schlobitten; and Charlotte, Abbess of Quedlinburg.
Dorothea married Georg Frederick Karl of Brandenburg-Bayreuth-Kulmbach, later Margrave of Bayreuth, on 17 April 1709 in Reinfeld. They had five children, two sons and three daughters.
The union was completely unhappy. In 1716, Dorothea was convicted of adultery and imprisoned in Nürnberg; eight years later, in 1724, the marriage was formally dissolved, but Dorothea remained in her prison. In 1726, her former husband ascended to the throne. At the death of her former husband in 1735, she was released.
Officially pronounced dead, she went to Sweden, where she lived under the name Dorothea von Ziedewitz, first as the guest of Governor von Brehmen and then with his widow outside Kalmar, and finally with the Lewenhaupt family on Stäflö for a payment of §1000, where she died, aged seventy-six. By that time, all her children, except the Margrave Frederick of Bayreuth -who died two years later (1763), had predeceased her.
- Sophie Christiane Luise (b. Weferlingen, 4 January 1710 – d. Brussels, 13 June 1739), married on 11 April 1731 to Alexander Ferdinand, 3rd Prince of Thurn and Taxis.
- Frederick (b. Weferlingen, 10 May 1711 – d. Bayreuth, 26 February 1763), successor of his father as Margrave of Bayreuth.
- Wilhelm Ernst (b. Weferlingen, 26 July 1712 – d. Mantua, 7 November 1733).
- Sophie Charlotte Albertine (b. Weferlingen, 27 July 1713 – d. Ilmenau, 2 March 1747), married on 7 April 1734 to Duke Ernst August I of Saxe-Weimar.
- Sophie Wilhelmine (b. Weferlingen, 8 July 1714 – d. Aurich, 7 September 1749), married on 25 May 1734 to Prince Charles Edzard of East Frisia.