Ivan VI Antonovich of Russia (Ivan Antonovich; Иоанн VI; Иоанн Антонович), (August 23, 1740 - July 16, 1764), reigned as Emperor of Russia 1740 - 1741. He was born in Saint Petersburg to Prince Antony Ulrich of Brunswick-Lüneburg and the princess Anna Leopoldovna of Mecklenburg.
On the accession of Peter III (1762) the condition of the unfortunate prisoner seemed about to improve, for the new emperor visited and sympathised with him; but Peter himself lost power a few weeks later. In the instructions sent to Ivan’s guardian, the latter received orders to chain up his charge, and even to scourge him should he become refractory.
On the accession of Catherine II (summer 1762) still more stringent orders were sent to the officer in charge of "the nameless one". If any attempt were made from outside to release him, the prisoner was to be put to death; in no circumstances was he to be delivered alive into anyone's hands, even if his deliverers produced the Empress’s own sign manual authorising his release. By this time, twenty years of solitary confinement had disturbed Ivan's mental equilibrium, though he does not seem to have been actually insane. Nevertheless, despite the mystery surrounding him, he was well aware of his imperial origin, and always called himself Gosudar (Sovereign). Though instructions had been given to keep him ignorant, he had been taught his letters and could read his Bible. Nor could his residence at Shlisselburg remain concealed forever, and its discovery was the cause of his ruin. A sub-lieutenant of the garrison, Vasily Mirovich, found out about him, and formed a plan for freeing and proclaiming him Emperor. At midnight on July 5, 1764, Mirovich won over some of the garrison, arrested the commandant, Berednikov, and demanded the delivery of Ivan. His jailers, on orders of their commander, an officer surnamed Chekin, murdered him then and there in obedience to the secret instructions already in their possession. He was buried quietly in the fortress, and his death secured Catherine II's position on the throne until her son came of age.