Peter the Great (1672–1725), who became ruler in his own right in 1696, was destined to bring the Tsardom of Russia, which had little contact with Europe and was mostly seen as a regional power, into the mainstream of European culture and politics. After suppressing numerous rebellions with considerable bloodshed, Peter embarked on a tour of Western Europe incognito. He became impressed with what he saw and was awakened to the backwardness of Russia, a nation that resembled a Mongol khanate more than a European monarchy. Peter began requiring the nobility to wear Western clothing and shave off their beards, an action that the boyars protested bitterly. Arranged marriages among nobility were banned and the Orthodox Church brought under state control. Military academies were established to create a modern European-style army and officer corps in place of the disorganized levies that Muscovite rulers had traditionally used.

These changes did not win Peter many friends and in fact caused great political division in the country. These along with his notorious cruelties (such as the torture death of his own son for plotting a rebellion) and the immense human suffering that accompanied many of his projects such as the construction of Saint Petersburg led many pious Russians to believe that he was the Antichrist. The Great Northern War against Sweden consumed much of Peter's attention for years, however the Swedes were eventually defeated and peace agreed to in 1721. Russia annexed the Baltic coast from Sweden and parts of Finland, which would become the site of the new Russian capital, Saint Petersburg. The Russian victory in the Great Northern War marked a watershed in European politics, as it not only brought about the eclipse of Sweden and Poland as great powers, but also Russia's decisive emergence as a permanent factor in Europe. Expansion into Siberia also continued and war with Persia brought about the acquisition of territory in the Caucasus, although Russia surrendered those gains after Peter's death in 1725.