The Parochial History of Cornwall…
“ The earldom and dukedom of Cornwall have, since his time, done no more than afford a revenue and bestow a name, like the shadows of a shade, with which the private gentlemen, holding hereditary seats in Parliament at the present time, continue to decorate themselves, by assuming the verbal denominations of offices extinct above three centuries, and which habit alone enables us to pronounce, as applicable to them, without a smile; but which offices, like the ancient earldom of Cornwall, while they had any existence, conferred real feudal sovereignty, proportionate to their different degrees. ”
