Chesten Marchant or Cheston Marchant, who died in 1676 at Gwithian, Cornwall, [1] reportedly having reached the age of 164 (the claim apparently going back to either William Scawen [2] or, according to Henry Jenner, to William Borlase [3] ), is believed to have been the last monoglot Cornish speaker, as opposed to other speakers such as Dolly Pentreath who could also speak English.
Cornish people seem to live to great ages, though some of the records of longevity should, perhaps, be treated with a certain reserve. C. S. Gilbert gives a long list of centenarians, and super-centenarians, including a woman named Chester [ sic ] Marchant who lived in Gwithian, and who, in 1676, according to one Mr. Scawen, reached the astounding age of 164 years.
It is recorded by Dr. Borlase that Cheston Marchant, who died at Gwithian in 1676 aged 164 (!), could speak nothing but Cornish.