On July 9, 1762, the wife of Russia’s new emperor, Peter III, rallies the army regiments of St. Petersburg against her husband and is proclaimed Empress Catherine II, the sole ruler of Russia.

More commonly known as Catherine the Great, she would stay on the throne for the next 34 years, longer than any other female ruler in Russian history.

The former Sophie von Anhalt-Zerbst was born in 1729 in what is now Poland. Her father was a minor Prussian prince; her mother was a member of the house of Holstein-Gottorp, one of Germany’s most celebrated families. At 15, Sophie scored an invitation to Russia from Empress Elizabeth, the daughter of Peter the Great, who was searching for a bride for her nephew and chosen heir to the throne, the Grand Duke Peter, who was also Sophie’s cousin on her mother’s side. They were married the following year, and Sophie converted to Orthodox Christianity, adopting the name Catherine.

Peter and Catherine’s marriage was unhappy from the beginning, and neither one was faithful. Catherine later hinted in her memoirs that her husband hadn’t fathered any of her four children, but most historians believe he did father her first son, Paul, born in 1754.

Soon after the Empress Elizabeth died and Peter ascended to the throne in early 1762, his many enemies plotted to overthrow Peter and replace him with 7-year-old Paul. Instead, the ambitious Catherine acted quickly to seize the advantage for herself. With the help of her lover, Gregory Orlov, she won the military’s support and had herself proclaimed Russia’s sole ruler in July 1762, forcing her husband to abdicate his throne. Peter was assassinated just eight days later by Catherine’s supporters, casting some doubt on her legitimacy as ruler.

Despite this turbulent beginning, Catherine’s reign would be remembered as a time of significant progress and achievement for Russia. Like Peter the Great, she worked to Westernize the nation and make it strong enough to hold its own against the great powers of Europe. Under Catherine, Russia’s borders expanded to the west and south, encompassing Crimea as well as much of Poland.

Notorious for her many lovers, Catherine showed less affection for her son, Paul, whom she supposedly considered passing over as heir in favor of his son, Alexander. But before she could do so, Catherine died of a stroke in 1796, leaving Paul to inherit the throne. He was assassinated five years later, opening the way for Catherine’s adored grandson, Alexander I, to become the next ruler in the Romanov dynasty.