Does anyone have more information on Catherine's siblings Auguste, Wilhelm, Elisabeth and Friedrich?
With 4 siblings, 3 of them died during infancy:
Wilhelm Christian, prince of Anhalt-Zerbst, 1730-1742
Friedrich August, prince of Anhalt-Zerbst, 1734-1793*
Auguste Christina, princess of Anhalt-Zerbst, 1736-1736
Elisabeth Ulrika, princess of Anhalt-Zerbst, 1742-1745
* Friedrich August
1st wedding - 1753 - Caroline of Hesse-Cassel --> no childs.
2nd wedding - 1764 - Friedricha of Anhalt-Bernburg --> no childs.