Earl of Grantham was a title in the Peerage of England created once on 24 December 1698, along with the titles Viscount Boston, of Boston in the County of Lincoln, and Baron Alford, of Alford in the County of Lincoln, for Henry de Nassau d'Auverquerque. The titles were created with a special remainder, failing heirs male of his body, to his three brothers Cornelius, Maurice and Francis, in like manner respectively. Since both his sons and as well his three brothers had predeceased him, the titles became extinct upon his death in 1754.
Arms of the Earls of Grantham Henry de Nassau d'Auverquerque, 1st Earl of Grantham (1675–1754)
Henry, Viscount Boston (1697–1718)
Thomas, Viscount Boston (1700-1730)
Earl of Grantham Wikipedia
Screenwriter Julian Fellowes used the title, Earl of Grantham — although as a new fictional creation in the Peerage of Great Britain — for one of the main characters, Robert Crawley, in his 2010 ITV1 period drama Downton Abbey.