 His son was created Earl of Derby in 1485 and the titles remained united until the death of the fifth earl, without male heirs in 1594, when the barony became abeyant.On 7 March 1921, the abeyance was terminated in favour of the 12th Countess of Loudoun, but upon her death in 1960, it became abeyant among her daughters.The co-heirs are the descendants of the seventh baroness