Complex sentence: Jefferson's writings tell how his ancestors came from Wales to America in the early 17th century and settled in Virginia, in the western frontier of the colony, something that later helped Jefferson's defend individual and state rights.
Split into simpler sentences: Jefferson's writings tell how his ancestors came from Wales to America in the early 17th century. They settled in Virginia, in the western frontier of the colony, something that later helped Jefferson's defend individual and state rights.