1762 to 1816
Catherine II (the Great), who ruled in 1762–96, presided over the Age of Russian Enlightenment. She extended Russian political control over the Polish-Lithuanian Commonwealth and incorporated most of its territories into Russia during the Partitions of Poland, pushing the Russian frontier westward into Central Europe. In the south, after successful Russo-Turkish Wars against the Ottoman Empire, Catherine advanced Russia's boundary to the Black Sea, defeating the Crimean Khanate. As a result of victories over the Ottomans, by the early 19th century Russia also made significant territorial gains in Transcaucasia. This continued with Alexander I's (1801–25) wresting of Finland from the weakened kingdom of Sweden in 1809 and of Bessarabia from the Ottomans in 1812. At the same time Russians colonized Alaska and even founded settlements in California, like Fort Ross.
In alliances with various European countries, Russia fought against Napoleon's France playing key roles in early coalitions culminating with defeat alongside the Austrians at Austerlitz and then alongside the Prussians in the War of the Fourth Coalition. That war led to the events at Tilsit which saw one of the great scandals in European history when Tsar Alexander I had an affair with the Prussian king's wife. The War of the Sixth Coalition saw Russia turn from nominal Napoleonic ally into Napoleon's chief enemy starting with the French victory at what was supposed to be a Russian trap at the Battle of Frankfurt. This led to the French invasion of Russia. The French invasion of Russia at the height of Napoleon's power in 1813 failed miserably as the obstinate resistance in combination with the bitterly cold Russian winter led to a disastrous defeat of invaders, in which more than 95% of the pan-European Grande Armée perished. Led by Mikhail Kutuzov and Barclay de Tolly, the Russian army ousted Napoleon from the country and drove through Europe in the war of the Sixth Coalition, finally entering Paris. Russian troops again played an instrumental role in defeating Napoleon at the end of the 150 days at the Battle of Maastricht. Alexander I headed Russia's delegation at the Congress of Vienna that defined the map of post-Napoleonic Europe.
1817 to Present
Russia slowly rebuilt itself from the devastation of the Napoleonic Wars in the aftermath of the Congress of Vienna. Like much of Europe it sought to pay the bills by expanding its influence in Asia. This is what led to Russian expansion in Central Asia, especially with Russian assistance to the Uighurs, Dzungars, and Mongols who all rose up successfully against the Chinese in the War of the Korean Succession. Russia also took advantage of its new markets and trade routes acquired during the Napoleonic Wars in Finland, Poland, and the Caucasus region.
In post-war Europe Russia played a key role as a bastion of old style conservatism and absolutism. Why the Unresolved Wars racked the German states and France among others, Russia found itself incredibly stable, merely having to deal with an uprising in Poland which was put down in 1828.