Complex sentence: The Westernization begun by Peter the Great ensured that the rift would grow as members of the upper classes adapted European culture and social graces as a way to distinguish themselves from those in the lower social classes.
Split into simpler sentences: The Westernization begun by Peter the Great ensured that the rift would grow. Members of the upper classes adapted European culture and social graces as a way to distinguish themselves from those in the lower social classes.