Complex sentence: According to Livy, Brutus had a number of grievances against his uncle the king, amongst them was the fact that Tarquin had put to death a number of the chief men of Rome, including Brutus' brother.
Split into simpler sentences: According to Livy, Brutus had a number of grievances against his uncle the king. Amongst them was the fact that Tarquin had put to death a number of the chief men of Rome, including Brutus' brother.