Percy Wyndham-O'Brien, 1st Earl Of Thomond

Percy Wyndham-O'Brien, 1st Earl of Thomond (circa 1713 – 1774), was a British Member of Parliament and an Irish peer.

**Origins**

He was the younger son of Sir William Wyndham, 3rd Baronet (circa 1688–1740), and his wife Catherine Seymour. Sir William Wyndham was a Tory statesman who served as Secretary at War in 1712, Chancellor of the Exchequer in 1713, and as a Tory leader in the House of Commons during the reigns of King George I and the early years of King George II. Catherine Seymour was the daughter of Charles Seymour, 6th Duke of Somerset (1662–1748), and the sister of Algernon Seymour, 7th Duke of Somerset (1684–1750). The 7th Duke of Somerset was created Earl of Egremont and Baron Cockermouth in 1749, with a special remainder to his nephew Charles Wyndham (1710–1763), who became the 2nd Earl of Egremont in 1750.

**Inheritance**

In 1741, at approximately 28 years of age, Wyndham-O'Brien inherited Irish estates from Henry O'Brien, 8th Earl of Thomond, who had died without issue. O'Brien's will left the estates to Wyndham-O'Brien as the younger son of his wife's sister. Pursuant to the terms of the bequest, he adopted the additional surname O'Brien. On December 11, 1756, he was created Earl of Thomond and Baron Ibracken (the second creation of these titles).

**Education and Political Career**

Wyndham-O'Brien was educated at St Mary Hall, Oxford. His parliamentary career included representing Taunton, Somerset, as an MP from 1745 to 1747, succeeded by his elder brother Sir Charles Wyndham, 4th Baronet (1710–1763). He served as MP for Minehead, Somerset, from 1747 to 1754, and for Cockermouth, Cumberland, from 1754 to 1761. The Cockermouth and Egremont estates were historically associated with the Percy Earls of Northumberland, with ties to the Seymour family through the co-heir Charles Wyndham. Later, Wyndham-O'Brien was MP for Winchelsea from 1768 to 1774.

**Death and Succession**

Percy Wyndham-O'Brien died unmarried and without issue in 1774, resulting in the extinction of the earldom. His estates were inherited by his nephew George O'Brien Wyndham, the 3rd Earl of Egremont (1751–1837), of Petworth House in Sussex and Orchard Wyndham.

**References**

Additional biographical information can be found in the "History of Parliament" and in H. A. Wyndham's "A Family History, The Wyndhams of Somerset, Sussex and Wiltshire," published in 1950.