The Dukedom of Inverness was a title in the Jacobite Peerage

Jacobite peerage

After the deposition by the English parliament in February 1689 of King James II and VII from the thrones of England and Ireland , he and his successors continued to create peers and baronets, which they believed was their right...

 of Great Britain

Great Britain

Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

, and as such was not recognised by the government or monarch or Great Britain. Its only holder was John Hay of Cromlix

John Hay of Cromlix

John Hay of Cromlix was the Jacobite duke of Inverness and a courtier and army officer to the 'Old Pretender'. He was from the Clan Hay.-Life:...

.

Lady Cecilia Underwood

Cecilia Underwood, Duchess of Inverness

Cecilia Underwood, 1st Duchess of Inverness was the second wife of Prince Augustus Frederick, Duke of Sussex, sixth son of King George III. As their marriage was in contravention of the Royal Marriages Act 1772, it was considered legally void, and she could not be styled either as the Duchess of...

 was the second wife of Prince Augustus Frederick, Duke of Sussex

Prince Augustus Frederick, Duke of Sussex

The Prince Augustus Frederick, Duke of Sussex , was the sixth son of George III of the United Kingdom and his consort, Charlotte of Mecklenburg-Strelitz. He was the only surviving son of George III who did not pursue an army or naval career.- Early life :His Royal Highness The Prince Augustus...

, the sixth son of King George III

George III of the United Kingdom

George III was King of Great Britain and King of Ireland from 25 October 1760 until the union of these two countries on 1 January 1801, after which he was King of the United Kingdom of Great Britain and Ireland until his death...

; however, their marriage was deemed illegal because of the Royal Marriages Act 1772

Royal Marriages Act 1772

The Royal Marriages Act 1772 is an Act of the Parliament of Great Britain which prescribes the conditions under which members of the British Royal Family may contract a valid marriage, in order to guard against marriages that could diminish the status of the Royal House...

, so Cecilia was never recognized as Duchess of Sussex

Duke of Sussex

Duke of Sussex was a title in the Peerage of the United Kingdom. It was conferred on 27 November 1801 upon The Prince Augustus Frederick, the sixth son of George III, who was created Duke of Sussex, Earl of Inverness, and Baron Arklow, all in the Peerage of the United Kingdom...

 or a British princess

British princess

This is a list of British princesses from the accession of King George I in 1714. This article deals with both princesses of the blood royal and women who become princesses upon marriage....

. Instead, Queen Victoria

Victoria of the United Kingdom

Victoria was the monarch of the United Kingdom of Great Britain and Ireland from 20 June 1837 until her death. From 1 May 1876, she used the additional title of Empress of India....

later created Cecilia Duchess of Inverness for life.