POWIS, EARLS AND MARQUESSES OF. Before the Norman Conquest the Welsh principality of Powis, comprising the county of Montgomery and parts of the counties of Bretknock, Radnor, Shropshire, Merioneth and Denbigh, was subject to the princes of North Wales. Early in the 12th century it was divided into upper and lower Powis. In 1283 Owen ap Griffin, prince of upper Powis, formally resigned his princely title (nomen et circulum principatus) and his lands to the English king Edward I. at Shrewsbury, and received the lands again as an English barony. (See Montgomeryshire Collections, 1868, vol. i.) This barony of Powis passed through female inheritance to the family of Cherleton and in 1421 to that of Grey. It fell into abeyance in 1551.
Montgomery and marquess of Powis in 1687. The recognized head of the Roman Catholic aristocracy in England, Powis was suspected of complicity in some of the popish plots and was imprisoned in the Tower of London from 1678 to 1684. He followed James II. into exile and was created duke of Powis by the dethroned king. William, 2nd marquess, who had a somewhat chequered career as a Jacobite, died in October and when his son William, the 3rd marquess, died in 1748 the titles became extinct.
In 1748 Henry Arthur Herbert (d. 1772), who had been made Baron Herbert of Cherbury in was created Baron Powis and earl of Powis. The titles became extinct a second time when his son George Edward died in January 1801. George's sister and heiress, Henrietta Antonia (1758-1830), married Edward Clive (1754-1829), son and heir of the great Lord Clive. In 1803, he was created Baron Powis and earl of Powis.