The title of Viscount Valentia was created in the Peerage of Ireland in 1622. For some time in the 17th and 18th centuries, its holders were also Earls of Anglesey, but this title became extinct in 1761.
The Viscount holds the subsidiary title of Baron Mountnorris (1628), also in the Peerage of Ireland. The 8th Viscount, who had not been allowed to succeed to the English Earldom of Anglesey, was created Earl of Mountnorris in the Peerage of Ireland, but this title became extinct upon the death of the 2nd Earl in 1844. The 11th Viscount was created Baron Annesley of Bletchington in the Peerage of the United Kingdom in 1917, but this title became extinct on the death of the 12th viscount in 1949.
In November 1660 by his father's death he had become Viscount Valentia and Baron Mountnorris in the Irish peerage, and on the 20th April 1661 he was created Baron Annesley of Newport Pagnell in Buckinghamshire and earl of Anglesey in the peerage of Great Britain.
He supported the king's administration in parliament, but opposed strongly the unjust measure which, on the abolition of the court of wards, placed the extra burden of taxation thus rendered necessary on the excise.
He was created in 1793 earl of Mountnorris in the peerage of Ireland.