Thomas Fitzwilliam, 4th Earl of Southampton, was an English nobleman born in 1600. He was the son of Thomas Fitzwilliam, 3rd Earl of Southampton and Mary Browne. He inherited the title of Earl of Southampton in 1643, during a tumultuous period in English history marked by the English Civil War. The 4th Earl was known for his loyalty to the Royalist cause, supporting King Charles I. He was involved in various military campaigns and held several important positions, including serving as a member of the House of Lords. He passed away in 1667, leaving behind a legacy tied to the tumultuous events of his time.