Fitzwilliam was first cousin to Henry, 10th Earl of Pembroke. In 1788 when Pembroke hoped that his heir would be called up to the Lords, he informed him: ‘Your vacancy might accommodate Lord Fitzwilliam, and possibly serve to forward his other plan’. This ‘other plan’ was an English title, which, however, Pembroke thought, 3 Jan. 1789, and so he informed his son, ‘was never ... so probable as he flattered himself; and now it is, I fear, more than ever out of his and our reach; but he flatters himself still, I see’.
In 1790 Fitzwilliam came in for Pembroke’s borough of Wilton: the patron had decided to displace William Gerard Hamilton in April 1789 after Hamilton had voted with opposition, and thought Fitzwilliam would ‘be glad to succeed him’. His son agreed that Fitzwilliam would be ‘in every shape a very proper person’ and reported to his father, 21 May 1789:
In a letter from Lord Fitzwilliam are the following words. ‘With regard to Wilton, disposez de moi, but do not let me stand either in yours or Lord Pembroke’s way.’ He has likewise told me he should be happy to be elected at Wilton, which you had proposed to him and that he had on a former occasion signified as much to you, but that he did not possess the shadow of a claim upon you.
Pembroke Pprs. 408, 422, 428.
After this, nothing: no vote either way, no speech, no indication of attendance. In April 1791, admittedly, he was listed hostile to the repeal of the Test Act in Scotland. The Treasury compilers of party lists, baffled, labelled him ‘doubtful’ in September 1804 and, better still, ‘nil’ in July 1805. In February 1806 he resigned in favour of another member of Pembroke’s family. He had been, in effect, a stop-gap for the family interest.
A connoisseur, Fitzwilliam was the anonymous author of a series of Letters of Atticus, published in London in French, 1811, on ‘Protestantism and Catholicism considered in their comparative influence on society’, which showed considerable detachment. Succeeded in the title by two brothers who left no issue, he left his property to Lord Pembroke and his fine collection of pictures, drawings, books and manuscripts to his university, with the dividends on £100,000 of South Sea stock to erect a museum at Cambridge to house them.
