1802 he became the 2nd Earl Grosvenor. Grosvenor was Mayor of Chester in 1807–08, and was responsible for the building of Thomas Harrison's Northgate in the city in 1810. He served as Lord Lieutenant of Flintshire from 1798 to 1845. When Grosvenor entered parliament, he continued the family tradition of being a Tory and supporting William Pitt the Younger. However, after Pitt's death in 1806, he changed his allegiance and became a Whig. This led to his support for the victims of the Peterloo massacre, for Catholic Emancipation, for the abolition of the Corn Laws, and his voting for the Reform Bill. He was a man of principle; he championed Queen Caroline and is reputed to have thrown either a Bible or a Prayer Book at the head of King George IV. And when the Duke of Wellington was presented with the freedom of the city of Chester, Grosvenor refused to allow the town hall to be used for the event. The relations between Grosvenor and the king later improved, and in the coronation honours of 1831 he was created Marquess of Westminster. He participated in the coronation of Queen Victoria in 1837. On 11 March 1841 he was received as a Knight of the Garter. Development of the estate Soon after Robert Grosvenor inherited the Eaton estate, he rebuilt the country house at Eaton Hall in Cheshire, and he also developed the London estate, creating the areas now known as Belgravia and Pimlico. Eaton had become "an unfashionable and run-down estate". The existing country house had been built for his grandfather, Sir Thomas Grosvenor, 3rd Baronet and designed by William Samwell. He appointed William Porden as architect, who had previously surveyed his London estate. The original plan was for the new house to cost £10,000 (equivalent to £ as of ), and for it to take two years to build. In the event it took just under ten years and cost over £100,000 (equivalent to £ as of ). The previous house was encased and surrounded by "every possible permutation of the gothic style". It included turrets, pinnacles, arched windows, octagonal towers, and buttresses (both regular and flying). Four new wings were added to the house. When the future Queen Victoria visited in 1832 at the age of 13, she wrote in her journal: "The house is magnificent". However others described it as being "as extravagant and opulent as