Again in the 18th century, the heiress Elizabeth Seymour married Sir Hugh Smithson, who adopted the surname Percy and was created Duke of Northumberland.

[citation needed] After arriving in England following the Harrying of the North (1069–70), he was bestowed modest estates in Yorkshire by Hugh d'Avranches.

However, by the reign of Henry II the family was represented by only an heiress, Agnes de Percy (died 1203) following the death of the third feudal baron.

The castle had been founded in the late 11th century by Ivo de Vesci, a nobleman from Vassy or Vichy.

Due to being under age, King Henry III of England conferred the wardship of John's estates to a foreign kinsman, which caused great offence to the de Vesci family.

From this time, the fortunes of the Percys, although they still held their Yorkshire lands and titles, were linked permanently with Alnwick and its castle.

In 1346, Henry commanded the right wing of the English Army which defeated a larger Scottish force at the Battle of Neville's Cross near Durham.

He supported the takeover by Henry IV but subsequently rebelled against the new king, leading to his estates being forfeited under attainder.

In his rebellion he was aided by his son, the most famous Percy of all, Henry "Hotspur", who was slain at Shrewsbury in the lifetime of his father.

[9] Both the 1st Earl of Northumberland as well as his son Hotspur play a chief role in Shakespeare's Henry IV.

[9] The fourth Earl was involved in the political manoeuvrings of the last Yorkist kings Edward IV and Richard III.

[citation needed] The fifth Earl displayed magnificence in his tastes, and being one of the richest magnates of his day, kept a very large household establishment.

[10][11] The above steps formed a deliberate move to allow ancient names and titles of the Percys to be revived in the male-heir exhausted senior branch of the Dukedom of Somerset, which at that time was about to see its largest removal – to another noble but very cadet branch (a fourth cousin) on Algernon's death.

In 1957, on the death of his fourth cousin once removed, James Stewart-Murray, 9th Duke of Atholl, Hugh succeeded as 9th Baron Percy, the title thus re-merging with the Dukedom.

[22] Warkworth and Prudhoe castles were the residences of the Earls of Northumberland in the Middle Ages, and ownership was retained by the later Dukes.

Albury Park is a former residence which has been converted into apartments, while the surrounding estate is still directly owned by the Duke.

[23] The traditional burial place of the Dukes is the Northumberland Vault in Westminster Abbey in London, the Percys thus being the last family to maintain such a privilege.