The Earldom of Darnley has been created in both the Peerage of Scotland and the Peerage of Ireland. In the Peerage of Scotland, the Earldom has been twice created, each time along with the Dukedom of Lennox. (See that page for more information on the Scottish creations.)
In Ireland, the title was created in 1725 for John Bligh. The Earl's other titles are: Viscount Darnley of Athboy (created 1723; Peerage of Ireland), Baron Clifton of Leighton Bromswold (created 1608; Peerage of England) and Baron Clifton of Rathmore (created 1721; Peerage of Ireland).
JOHN GRIFFIN GRIFFIN, baron Howard of Walden and baron Braybrooke of Braybrooke; knight of the bath, lord lieutenant and custos rotulorum of the county of Essex, a general of his majesty's forces, colonel of the fourth regiment of dragoons, and recorder of the borough of Walden in the county of Essex.
Baron Braybrooke of Braybrooke in the county of Northampton 30 August 1788.
WILLIAM CRAVEN, baron Craven of Hampsted Marshal; lord lieutenant and custos rotulorum of the county of Berks, and colonel of the militia of that county, high steward of the borough of Newberry in the county of Berks, and doctor of laws.
This William Clifton sought his fortune in London and married Elizabeth, daughter of Thomas Blount, and having acquired great wealth, bought Barrington which he left to his son Sir Gervase, created Lord Clifton, who was therefore cousin of the "gentle" Sir Gervase Clifton of Clifton.
Catherine was first of all Miss Clifton; then Baroness Clifton in her own right: then by her marriage she became Lady Esme Stuart; upon her husband being created an Earl in 1619, she became Countess of March; and when he succeeded his brother in 1624 as third Duke, she became Duchess of Lennox.
The family, which by the marriage of the last Sir Robert Clifton's only sister to Sir Hervey Bruce, 3rd Bart, of Downhill, Londonderry in 1842, became representative of the Cliftons of Clifton, is credited by Burke and Debrett with "common origin" with King Robert Bruce, the hero of Bannockburn.