The traditional Welsh spelling is itself a modified form of the original name of antiquity, Caer-yn-Arfon, meaning fortification opposite the island of Mona (now called Ynys Môn, or Anglesey in English).

He had previously represented Wilton in the House of Commons and had already in 1780 been created Baron Porchester, of High Clere in the County of Southampton (also in the Peerage of Great Britain).

His eldest son Henry John George Herbert, the third Earl, briefly represented Wootton Bassett in Parliament as a Tory before he succeeded his father in the earldom.

His eldest son Henry Howard Molyneux Herbert, the fourth Earl, was a prominent Conservative politician and served as Secretary of State for the Colonies and as Lord Lieutenant of Ireland.

In 1905, their only son Auberon Herbert succeeded his uncle as ninth Baron Lucas of Crudwell (see this title for further history of this branch of the family).

The family seat of the Herbert Earls of Carnarvon is Highclere Castle in Hampshire, which was the filming location for the UK television series Downton Abbey.

[6] As of 2020[update], the heir apparent is the present holder's elder son, George Kenneth Oliver Molyneux Herbert, Lord Porchester (born 1992).