First, let me say that I truly believe that Prince Harry and Meghan Markel will be granted the titles of Duke and Duchess of Sussex. However, I would like to make the case that the Duke of Clarence should be strongly considered.
Royal Dukedoms have generally followed one of two patterns:
1) From the original list of 5 dukedoms established by King Edward III; Cornwall, Clarence, Lancaster, York & Gloucester.
2) Dukedoms or Earldoms from the geographic names of the Heptarchy (the 7 Anglo-Saxon Kingdoms of England prior to the unification under King Egbert); Northumbria, Kent, Wessex, Sussex, Essex, East Anglia & Mercia. Two of these larger kingdoms have been broken down into smaller geographic subdivisions. For example, East Anglia now encompasses the titles of Norfolk, Suffolk and Cambridge.
When evaluating the original list of 5 from above, all are in use by a member of the current House of Windsor, except Clarence which is vacant. When evaluating the list from the Heptarchy, most are in use. Kent and Wessex by the House of Windsor, Northumria by the House of Percy, Essex by the House of Capell, East Anglia and its geographic subdivisions are held by the Houses of Howard or Windsor. Mercia could be argued that there are geographic opportunities and finally Sussex which is vacant.
At this point, the choice between Clarence and Sussex is a toss-up. Some would (and do) argue that Clarence should not be chosen due to some of the negative character associations connected to this title. However, we have recently learned that Prince Harry and Meghan Markel share common royal ancestry, both descending from Lionel of Antwerp, the 1st Duke of Clarence, the second son of King Edward III (according to American Ancestors by the New England Historic & Genealogical Association). This fact alone tips the scales for me. For those that still argue against the title of Clarence, I would suggest, what better couple could change the perception of the Clarence title in a more positive light than Prince Harry and Meghan?
As mentioned above, I do believe Sussex is going to be the more likely choice, however, there is an opportunity for the House of Windsor to grant and hold the final title from the “original list of 5” all within the current royal family.
We now wait and see.