Russia began as Kievan Rus in the 600s-1200s, a collection of feudal states. It was later conquered by the Mongol Empire from 1200s-1400s. After their withdrawal, Russia was engulfed in civil wars between powerful families until the Romanov Dynasty began in 1613, restoring independence. Over the next centuries, the Russian Empire expanded greatly through conquest, absorbing new lands and peoples to its west, east, and south. It modernized under Peter the Great in the early 1700s but remained a largely traditional, agricultural society dominated by nobles, with serfdom and social unrest widespread.