"celebrated beau of Catherine the Great's day"

 Catherine the Great (1729-1796) ruled as Empress of Russia from 1762-1796. During her reign Russia became one of the most powerful empires in Europe.

Born as Sophia von Anhalt-Zerbst-Dornburg in Stettin, Germany, Catherine rose to power after her eccentric husband Tsar Peter III was assassinated six months into his reign. Despite her German origin, Catherine succeeded the throne, following the precedent set by Empress Catherine I in 1725. Although she had many lovers during her reign, most notably Grigori Alexandrovich Potemkin, she never openly remarried, retaining her independence and power over the Russian Empire. Her reign saw the expansion of the Russian Empire and of its power in Europe, as well as a flowering of art and culture within its borders. Catherine was a proponent of the Enlightenment, and took a serious interest in liberal Western European philosophies, corresponding with the French philosophers Diderot and Voltaire. She applied these ideas in modernizing aspects of the Russian government, although she failed to extend her liberalism to the issue of serfdom in Russia.

A good short biography of the empress is Catherine the Great (Life & Times) by Michael Streeter, pub. Haus Publishing.