During the seventeenth century both the shire and borough of Carmarthen were dominated by the Vaughans of Golden Grove. In 1713 the male line of the main branch of the family ended with the death of the 3rd Earl of Carbery. His only daughter and heiress married the Marquess of Winchester, who was returned as a Whig in 1715. He vacated his seat on being summoned to the House of Lords in 1717, thus clearing the way for other local families to assert old or new claims to a share in the county representation. The vacancy was filled by a stop-gap, Sir Thomas Stepney of Llanelly, but a bitter contest occurred in 1722 between two rival Whig candidates, Sir Nicholas Williams of Edwinsford and Edward Rice of Newton. In March the new Duke of Bolton wrote to Williams urging him to give way:

I am very sorry to hear that you still persist in occasioning a contested election in Carmarthenshire, when you always knew that I could not be for you this time. There can be nothing so agreeable to me as to see that county quiet and unanimous. Therefore I shall take it as a particular favour if you will accommodate this matter with Mr. Rice for this next election: which, if you will do it, it will oblige me so much that the next time I will give you my interest, having no matter of objection to your person or principle, and I am very sorry that you happened so hastily to be against me when I stood myself. I have declared for Mr. Rice.1

At the poll Rice was successful by five votes, but Williams gained the seat on petition,2 retaining it till his death in 1745. He was succeeded by another Whig, John Vaughan of Derwydd, second cousin to the Duchess of Bolton, who bequeathed him the Golden Grove estate on her death in 1751.