Elisabeth Katharina Christine of Mecklenburg-Schwerin in 1722 had arrived in Russia with her mother, who had escaped and separated from her father, Charles Leopold, the Duke of Mecklenburg-Schwerin: her mother, Tsarevna Catherine of Russia (sister of Empress Anna), had been considered as a candidate to the throne in 1730, but her aunt had been chosen instead.

Elisabeth in 1733 had converted to the Orthodox religion and been given the name Anna Leopoldovna, which had made her acceptable as an heir to the throne.

She had in 1739 married Anthony Ulrich (1714–1776), son of Ferdinand Albert, Duke of Brunswick-Wolfenbüttel: he had been taken to Russia already in 1733, so that she could get to know him.

The empress Anna had on October 5, 1740, adopted their newborn son Ivan and proclaimed him heir to the Russian throne.

The empress dies on October 28, a few days after this proclamation, leaving directions regarding the succession, and appointing her favorite Ernest Biron, Duke of Courland, as regent.

Biron, however, has made himself an object of detestation to the Russian people, and after Biron threatens to exile Anna and her spouse to Germany, Anna Leopoldovna on November 8 has little difficulty in overthrowing him.

She now assumes the regency, and takes the title of Grand Duchess, but she knows little of the character of the people with whom she has to deal, knows even less of the conventions and politics of Russian government, and speedily quarrels with her principal supporters.

The Russo–Swedish War of 1741–1743, known as the Hats' Russian War in Sweden and the Hats' War in Finland, which results in the Lesser Wrath, or the occupation of Finland, is instigated by the Hats, a Swedish political party that aspires to regain the territories lost to Russia during the Great Northern War, and by French diplomacy, which seeks to divert Russia's attention from supporting its long-standing ally, the Habsburg monarchy, in the War of the Austrian Succession.

While eight thousand Swedish and Finnish troops are being deployed at the Russian border, near Lappeenranta (Swedish: Villmanstrand) and Hamina (Swedish: Frederikshamn), Sweden declares war on August 8.

The objective of these maneuvers is to threaten Saint Petersburg and to set the stage for a coup d'état, engineered by French and Swedish diplomats and aimed at toppling the pro-Austrian regime of Anna Leopoldovna.

Henrik Magnus von Buddenbrock, born on July 22, 1685, in Swedish Livonia, was the son of the landed gentleman and Swedish Empire army officer Henrik Gotthard von Buddenbrock (1648-1727) and Charlotta Cronman.

He had enlisted as an officer of the Swedish army, becoming a captain of the Livgardet in 1711, Major of grenadiers in 1715, and Major General in 1721.

He had been elevated to friherre (matricle number 206) in 1731 and promoted to Lieutenant General of the infantry in 1739.

As such, he is in 1741 commander of the troops in Finland, under General Charles Emil Lewenhaupt, at the onset of the Russo-Swedish War.

Major General Carl Henrik Wrangel, who leads one of the two divisions of the Swedish Army in Finland, with a strength of four thousand men, is ordered by Buddenbrock to lead his force into battle against General Peter Lacy's numerically superior Russian force in order to defend Villmanstrand, at the long disputed frontier between Sweden and Russia.

Anna Leopoldovna presides over a brilliant victory by Russian forces at the Battle of Villmanstrand in Finland after Sweden had declared war against her Government.

She has an influential favorite, Julia Mengden, daughter of the Livonian baron Magnus Gustav von Mengden.

Having participated in the coup that placed Anna Leopoldovna in power in 1740, Juila had been named the official nurse of Ivan VI of Russia.

The battle of Villmanstrand is fought in Karelia during the Russo-Swedish War on August 23, 1741 (September 3, NS), when twenty thousand Russian forces, under the command of General Peter von Lacy, advance from Vyborg (Swedish: Viborg, Finnish: Viipuri) to assault Villmanstrand (Finnish: Lappeenranta).

Fighting begins around two PM, but the Swedes withdraw at five PM before Swedish baron and Lieutenant General Henrik Magnus von Buddenbrock, less than ten kilometers away, can come to the assistance of General Wrangel.

Swedish casualties amount to two thousand men killed or wounded and  one thousand captured, among them Wrangel, who had lost his right arm during the battle.

Russia loses twenty-four hundred men.

The threat to the Russian capital thus relieved, Lacy does not continue his movement after the battle.

Elizabeth had been gathering support in the background during the reign of her cousin Anna; but after the death of Empress Anna, the regency of Anna Leopoldovna with infant Ivan VI has been marked by high taxes and economic problems.

Such a course of events compels the indolent, but by no means incapable, beauty to overthrow the weak and corrupt government.

Elizabeth, being the daughter of Peter the Great, enjoys much support from the Russian guards regiments, often visiting the regiments, marking special events with the officers and acting as godmother to their children.

The guards repay her kindness when on the night of November 25, 1741 OS (December 6 NS), Elizabeth seizes power with the help of the Preobrazhensky Regiment.

Arriving at the regimental headquarters dressed in a metal breastplate over her dress and grasping a silver cross she states, "Who do you want to serve? Me, the natural sovereign, or those who have stolen my inheritance?"

After winning the regiment over, ...

...the troops march to the Winter Palace where they arrest the infant Emperor, his parents and their own lieutenant-colonel, Count von Munnich.

It is a daring coup and passes without bloodshed.

This coup has the support of the ambassadors of France and Sweden, possibly with financial inducements to members of the Guard's regiments who want o change the pro-British and pro-Austrian policies of Anna Leopoldovna's Government.

Elizabeth has vowed that if she becomes Empress that she will not sign a single death sentence, an unusual promise that she—notably—will keep to throughout her life.

However, the new Tsarina reneges on her promises to return the Baltic provinces to Sweden and continues the vigorous prosecution of the war, under the guidance of her pro-Austrian chancellor, Aleksey Bestuzhev.

Elizabeth, naturally indolent and self-indulgent, and possessing little knowledge and no experience of affairs, had found herself at the age of thirty-three at the head of a great empire at one of the most critical periods of its existence.

Her proclamation as Empress Elizabeth I explains that the preceding reigns had led Russia to ruin: "The Russian people have been groaning under the enemies of the Christian faith, but she has delivered them from the degrading foreign oppression." (Antonov, Boris (2006). Russian Tsars. p. 106. Saint Petersburg: Ivan Fiorodov Art Publishers.)

Russia has been under the domination of German advisers and Elizabeth exiles the most unpopular of them, including Heinrich Ostermann, Burkhard von Munnich and Carl Gustav Lowenwolde.

Elizabeth crowns herself Empress in the Dormition Cathedral on April 25, 1742.