On a visit to Paris in 1791, Holland became acquainted with Lafayette and Talleyrand. He took his seat in the House of Lords on 5 October 1796. According to the 1911 edition of the Encyclopædia Britannica he for a while "almost... constituted the Whig party in the upper house." He was appointed to negotiate a treaty with American envoys James Monroe and William Pinkney, was admitted to the Privy Council on 27 August 1806, and on 15 October entered the Ministry of All the Talents led by Lord Grenville as Lord Privy Seal, retiring with the rest of his colleagues in March 1807. Holland led the opposition to the Regency bill in 1811, and he attacked the orders in council and other strong measures of the government taken to counteract Napoleon's Berlin decrees. He denounced the treaty of 1813 with Sweden which bound Britain to consent to the forcible union of Norway, and he resisted the bill of 1816 for confining Napoleon in Saint Helena. He was Chancellor of the Duchy of Lancaster between 1830 and 1834 and 1835 and 1840 in the cabinets of Lord Grey and Lord Melbourne, and he was still in office when he died in October 1840.
Holland's protests against the measures of the Tory ministers were collected and published, as the Opinions of Lord Holland, by Dr Moylan of Lincoln's Inn. Lord Holland's Foreign Reminiscences contain much amusing gossip from the Revolutionary and Napoleonic era. His Memoirs of the Whig Party is an important contemporary authority. He also published a small work on Lope de Vega and a 2-volume work on the lives and writings of Lope de Vega and Guillén de Castro.
Family
After visiting Paris in 1791 Holland again went abroad to travel in France and Italy in 1793. At Florence he met Elizabeth Vassall, at that time Lady Webster, wife of Sir Godfrey Webster, 4th Baronet. She and her husband obtained a divorce, and she married Holland on 6 July 1797, becoming Elizabeth Fox, Baroness Holland. An illegitimate son, Charles Richard Fox, was born to them. He later rose to become a General in the British Army. They had three more children who survived infancy: the Hon. Stephen Fox, Henry Edward Fox, 4th Baron Holland, and Hon. Mary Elizabeth Fox, married to Thomas Powys, 3rd Baron Lilford. In 1800 he was authorised to take the name of Vassall, and after 1807 he signed himself Vassall Holland, though the name was no part of his title. Lord Holland died in October 1840, aged 66, and was succeeded in his titles by his eldest and only surviving legitimate son, Henry. Lady Holland died in November 1845.
Vassall ward
in the London Borough of Lambeth is named after Henry Richard Vassall-Fox who was responsible for the first building development in the area in the 1820s. Roads in the area such as Holland Grove, Lord Holland Lane, Foxley Square and Vassall Road commemorate this connection.