Styled Viscount Newark from 1628, he was member of parliament for Nottingham[1] from 1628 until 1629, and was summoned to the House of Lords[2] in his father's Barony of Pierrepont in 1641. He succeeded his father as 2nd Earl of Kingston-upon-Hull in 1643.[2]
During the earlier part of the English Civil War he was at Oxford in attendance upon the King, whom he represented at the negotiations at Uxbridge. In 1645 he was made a Privy Counsellor and created Marquess of Dorchester; but in 1647 he compounded for his estates by paying a large fine to the parliamentarians.[1] Afterwards, Lord Dorchester, who was always fond of books, spent his time mainly in London engaged in the study of medicine and law, his devotion to the former science bringing upon him a certain amount of ridicule and abuse.[1] His collection of books is now part of the library of the Royal College of Physicians.
He was notorious for his bad temper and violent outbursts. He challenged his son-in-law, the future Duke of Rutland, to a duel in 1660; Dorchester blamed Rutland for the fact that his marriage to Dorchester's daughter Anne was notoriously unhappy. In 1638 he had to sue for a royal pardon for an assault on one Philip Kinder committed within the precincts of Westminster Abbey, during a religious service. In 1666, on a trivial pretext, he and George Villiers, 2nd Duke of Buckingham, came to blows in the Painted Chamber at Westminster during a Parliamentary conference. They were both imprisoned in the Tower of London for violating the dignity of Parliament as a result, but they were soon released after apologising.[3]
Dorchester survived his sons and when he died in London on 8 December 1680 the Marquessate of Dorchester became extinct. He was succeeded as 3rd Earl of Kingston-upon-Hull by Robert (died 1682), a son of Robert Pierrepont of Thoresby, Nottinghamshire, and as 4th Earl by Robert's brother William (died 1690).[1]
