Anna Leopoldovna (1718 - 18 March 1746), also known as Anna Karlovna, regent of Russia for a few months (1740 - 1741) during the minority of her baby son Ivan, was the daughter of Catherine (sister of the empress Anne) and of Charles Leopold, duke of Mecklenburg-Schwerin.
In 1739 she married Anton Ulrich (1714 - 1776), son of Ferdinand Albert, duke of Brunswick-Wolfenbüttel. On 5 October 1740 the empress Anne adopted their new-born son Ivan and proclaimed him heir to the Russian throne . A few days after this proclamation the empress died (28 October 1740), leaving directions regarding the succession, and appointing her favourite Ernest Biren, duke of Courland, as regent. Biren, however, had made himself an object of detestation to the Russian people, and Anna Leopoldovna had little difficulty in overthrowing him (8 November 1740). She then assumed the regency, and took the title of Grand-Duchess, but she knew little of the character of the people with whom she had to deal, knew even less of the conventions and politics of Russian government, and speedily quarrelled with her principal supporters.
In December 1741, the daughter of Peter the Great, who, from her habits, was a favourite with the soldiers, excited the guards to revolt, overcame the insignificant opposition, and ascended the throne as empress Elizabeth.
The victorious regime threw the erstwhile baby Tsar Ivan into prison, where he afterwards perished. Anna Leopoldovna and her husband sufferred banishment to a small island in the River Dvina, then to Kholmogory, where on 18 March 1746 she died in childbirth.
Original text from the 1911 Encyclopaedia Britannica.