Ivan was born on 23 August 1740 at Saint Petersburg, the eldest child of Duke Anthony Ulrich of Brunswick-Lüneburg by his wife, Duchess Anna Leopoldovna of Mecklenburg-Schwerin, the only niece of the childless Empress Anna of Russia, and the only granddaughter of Tsar Ivan V. She had lived in Russia almost all her life, and her husband had also made his home in that country, in the expectation that they or their progeny would inherit the throne upon the death of the empress.