Complex sentence: In 833, Mojmír I, Duke of the Moravians expelled Pribina who went to count Ratbod who administered the Eastern March of the Carolingian Empire.
Split into simpler sentences: In 833, Mojmír I, Duke of the Moravians expelled Pribina. Following his expulsion, Pribina went to count Ratbod who administered the Eastern March of the Carolingian Empire.