Complex sentence: The government of Rome, the "res publica", was already shared between original Romans and Latin and Sabines peoples--the Quinctia gens that had a great impact on Roman public life in those years was of Latin origin.
Split into simpler sentences: The government of Rome, the "res publica", was already shared between original Romans and Latin and Sabines peoples. For example, the Quinctia gens who had a great impact on Roman public life during that time was of Latin origin.