After his death in 1725, Russian succession was unsettled, and the throne was repeatedly seized in a series of coups that lasted decades. Only Catherine II (Catherine the Great), who reigned from 1762 to 1796, was able to secure a measure of stability. Catherine continued two of Peter's central programs: Westernization of Russian society, and increased expansion of the empire. The annexation of most of eastern Poland in the 1770s and 1790s worked toward both ends, increasing Russia's territory and giving it another foothold in Europe. Catherine promoted a number of eighteenth-century cultural institutions, including the Academy of Sciences (founded in 1725) and the University of Moscow (1755), which helped to make Russia -- especially Moscow and St. Petersburg -- into a center of European culture.
After the brief reign of Paul I (during which time Russia colonized Alaska), Catherine's grandson, Alexander I, assumed the throne in 1801, and sought to consolidate many of the developments of his predecessors by reforming the legal codes. But the invasion by Napoleon in 1812, although it ended in victory for the Russians, was costly, and left Russia considerably weakened.