Complex sentence: His paternal grandfather, Thomas Wharton, a native of Westmoreland, England, came to Pennsylvania around 1683; he served on the Philadelphia Common Council (1713--1718).
Split into simpler sentences: His paternal grandfather, Thomas Wharton, was a native of Westmoreland, England, and had emigrated to Pennsylvania around 1683. The senior Thomas served on the Philadelphia Common Council (1713--1718).