From then through the Arthurian period, such legendary dukes of Cornwall stood apart from the high king of Britain, while serving as his closest ally and, at times, as his protector (all per Monmouth's collected yarns).

[3] The historical record suggests that, following the Anglo-Saxon settlement of Britain, Cornwall formed part of a separate Kingdom of Dumnonia, which included Devon, although there is evidence that it may have had its own rulers at times.

Instead, from the (prevailing) Hanoverian perspective, it was as a result of his claiming his father's lost thrones that James was attainted for treason on 2 March 1702, and his titles were thus forfeited under English law.

[11] On 21 June 1968 a royal warrant augmented the aforementioned arms with the heir apparent's coronet, which consists of four crosses patée and four fleurs-de-lises with one arch (used only by the prince of Wales).

[13] All dukes of Cornwall who have been the eldest living son of the sovereign are generally considered to have held the same creation of the dukedom.

When Richard Plantagenet, Duke of York, pressed his claim to the throne, he was made heir apparent to Henry VI by the Act of Accord.

On 31 October 1460, he was made prince of Wales and earl of Chester, duke of Cornwall and Lord Protector of England.

Since he was not the eldest living son of the monarch, this creation was outside the terms of the 1337 warrant; York died in battle two months later, on 30 December 1460.

Charles Edward Stuart ('The Young Pretender'), eldest son and heir apparent of James Francis Edward Stuart ('The Old Pretender'), was born in Rome on 31 December 1720, and shortly after his birth, he was declared prince of Wales, duke of Cornwall and earl of Chester in the Jacobite succession.

With the death of the Old Pretender on 1 January 1766, he acceded to his father's claim to be King of England, Scotland, France, and Ireland.