Complex sentence: Charles FitzCharles, Earl of Plymouth (1657 -1680) was the illegitimate son of Charles II, by Catherine, daughter of Thomas Pegge of Yeldersley, Derbyshire.
Split into simpler sentences: Charles FitzCharles, Earl of Plymouth (1657 -1680) was born in or about 1657. He was the illegitimate son of Charles II, by Catherine, daughter of Thomas Pegge of Yeldersley, Derbyshire.