5. Catherine II, Empress of Russia Catherine the Great was a German princess. She married Prince Carl Peter Ulrich, the heir to Russian throne.
In June 1762, she took an active part in coup against her husband Peter III.
He was overthrown and soon killed in an accident, while Catherine became Russia's autocratic ruler.
Throughout her long reign, many reforms were undertaken, and territory of Russia was further extended by acquiring lands of southern Ukraine and Crimea.
She was one of the greatest of Russian rulers.