Catherine Sedley worked for Italian princess Mary of Modena, who had just married James, Duke of York, heir to the British throne. This eventually led to an affair with him. She was bewildered at having been chosen by James."It cannot be my beauty for he must see I have none," she remarked incredulously. "And it cannot be my wit, for he has not enough to know that I have any." James in fact was often attracted to women who were generally considered plain, if not ugly; his brother Charles II once joked that his confessor must impose these mistresses on him as a penance.
After his accession James yielded to pressure from his confessor Fr. Bonaventure Giffard, backed by Robert Spencer, 2nd Earl of Sunderland and several Catholic councillors to put her away for a time.[1] While James by his own account took Giffard's intervention "very kindly, he being a truly religious man" he told his councillors sharply "not to meddle in things that in no way related to them."
She was created Countess of Dorchester for life in 1686, an elevation which aroused much indignation and compelled Catherine to reside for a time in Ireland. In 1696 she married Sir David Colyear, Bt., who was created Earl of Portmore in 1703, and she was thus the mother of Charles Colyear, 2nd Earl of Portmore. After the Glorious Revolution when Queen Mary II refused to receive her at Court, Catherine inquired how Mary, who had broken the commandment to honour her father, was in any way better than Catherine, who had broken the commandment against adultery.
At the court of George I she met Louise de Kérouaille, Duchess of Portsmouth and William III's mistress Elizabeth Hamilton, Countess of Orkney and exclaimed "God! Who would have thought that we three whores should meet here." At George's coronation, in 1714 when the Archbishop of Canterbury, Thomas Tenison, ritually asked if the people accepted their new King, Catherine, observing the number of soldiers on duty, asked caustically " Does the old fool think that anyone will say No"?
She died at Bath on 26 October 1717, when her life peerage became extinct.