Complex sentence: Sir Charles Cornwallis (died 1629), was an English courtier and diplomatist, second son of Sir Thomas Cornwallis, and controller of Queen Mary's household, who had been imprisoned by Elizabeth in 1570.
Split into simpler sentences: Sir Charles Cornwallis (died 1629) was an English courtier and diplomat. He was the second son of Sir Thomas Cornwallis, controller of Queen Mary's household, who had been imprisoned by Elizabeth in 1570.