In Latin, ealdormans of Northumbrians were called Dux when they were vassals of Anglo-Saxon kings of England (Wessex). Bamburgh's lords (holders of Bernicia), Osulf I (d.963) and his son Waltheof I, founded a dynasty of Northumbrianduces. Soon after the Norman Conquest of England, the huge earldom was parceled out, and the dynasty's heirs were left with only a rump of it in Huntingdon and Northampton, in the 12th century holding only the title of earl.
The title Duke of Northumberland was created in 1551 for John Dudley. This appellation for his dukedom was chosen because, according to feudal custom, he and his family saw themselves as the rightful heirs of the Bamburgh dynasty, being descended from a daughter of Simon de St.Liz II, great-great-great-great-grandson of dux Waltheof I of the Northumbrians. Northumberland advanced the claim of his daughter-in-law, Lady Jane Grey, to the English throne, but when she was deposed by Queen Mary, Dudley was convicted of high treason and executed. A bastard son of his younger son and surviving heir, Robert Dudley, 1st Earl of Leicester, claimed the dukedom and used the title in early 17th century when in exile.
George Fitzroy, a bastard of king Charles II, was awarded the title in 1674, but it became extinct as Fitzroy left no heirs. The title was created for the third time in 1766 for heirs of a totally different family, the earlier earls of Northumberland, and it has been in the Percy family ever since. The seat of the Dukes of Northumberland is Alnwick Castle, in Alnwick, Northumberland; their London residence is Syon House in Brentford.
The subsidiary titles of the Duke of Northumberland are: Earl of Northumberland (created 1749), Earl Percy (1766), Earl of Beverley (1790), Baron Warkworth (1749) and Baron Lovaine (1784). All titles are in the Peerage of Great Britain. The courtesy title of the eldest son and heir to the Duke is Earl Percy.
In the BritishsitcomBlackadder, Lord Percy Percy, played by Tim McInnerny, is one of the main characters in the first two series. Actually two characters with almost identical personalities, Percy is the Duke of Northumberland in the first series, The Black Adder and heir to the same title in Blackadder II, he is shown as the inept and bumbling sidekick to the title character of the series, Edmund Blackadder.
