Elusive because reclusive, Chatham was an individual who is difficult to fathom. Lord Rosebery, possibly the most prominent example of a species that is extinct, the scholarly and literary Prime Minister, stressed Chatham's secret personality: ‘he revealed himself neither by word nor on paper, he deliberately enveloped himself in an opaque fog of mystery … seems to have cut off all vestiges of his real self as completely as a successful fugitive from justice. And so posterity sees nothing but the stern effigy … made himself a prebiographical figure.’ Written in 1910, this judgement is still essentially true. The intervening years have thrown up more material, but it is almost all comments on, rather than by, Chatham. In consequence the views of past biographers are of considerable value. They wrote in an age when the central achievement of Chatham's career, the defence and expansion of empire, was still a living reality, although his other major preoccupation, the nature of British politics, with specific reference to the influence of the Crown and the existence of party, had changed substantially by the Victorian and Edwardian period, years when so much more of the map was coloured red and when it was natural to search out and admire the founders of empire.