Notwithstanding the alienation of some of the estates consequent upon the extinction of the Earldom of Northumberland, Elizabeth Percy, the daughter of the last earl, was the most wealthy heiress in the realm; and, accordingly, it was considered to be a matter of the greatest importance that a suitable alliance should be arranged for her with the least possible delay. When but little more than a child, in 1679, she was married to Henry Cavendish, Earl of Ogle, and heir to the Duke of Newcastle, who died in the following year. Before another year had expired, the youthful widow was again married to Thomas Thynn of Longleat; but once more the heiress became a widow very shortly after her marriage. Her second husband was murdered early in 1682, as he was passing in his coach along Pall Mall. While she was still not more than fifteen years of age, within three months after the tragedy in Pall Mall, Elizabeth Percy became the wife of Charles Seymour, sixth Duke of Somerset, by whom only she had issue: she died in 1722, leaving, besides three daughters, one only surviving son, Algernon, who in 1748 succeeded his father as seventh Duke of Somerset. In 1749 this duke was created Baron of Warkworth and Earl of Northumberland, with remainder of those dignities to the heirs male of his daughter, his only surviving child, by her marriage with Sir Hugh Smithson. The duke died in 1750, when the Seymour dignities reverted to the male descendants of the Protector Somerset by his first marriage. Thus, once more, an only daughter, now bearing the paternal name of Seymour, was the heiress and representative of the Percy lords of Alnwick: and thus, by reason of his alliance with this lady, Sir Hugh Smithson became _jure uxoris_, by special Act of Parliament, Earl of Northumberland; and he himself, his countess, and their descendants, were empowered and authorised to take and use the surname of Percy alone, and to bear and quarter all the armorial insignia of that noble house.