Complex sentence: Zaccaria Franco, one of the nobles of her court, who loved her before she married the Duke of France, appears to be loyal to her, but in reality is scheming to become the absolute ruler.
Split into simpler sentences: Zaccaria Franco, one of the nobles of her court, who loved her before she married the Duke of France. He appears to be loyal to her, but in reality he is scheming to become the absolute ruler.