He was disloyal to three kings, heartless to his own relations, and apparently without scruple or honesty. However, he did have a good brain and an appreciation for the arts.
At 17 he went to the continent accompanied by a Dr. Pierce, and it is probably due to him that Althorp gained such a fine collection of baroque pictures. After the restoration he went to Oxford where he
befriended William Penn, the Quaker founder of Pennsylvania. When Penn was sent down, Sunderland left Oxford in sympathy.
In 1663 a marriage was arranged for him with Lady Anne Digby. However, when the settlements were signed and the trousseau prepared as well as the date fixed, Sunderland absconded. Again he went to the continent to buy pictures and have his portrait painted; but after a year he returned to England and married Lady Anne Digby after all.
Queen Anne regarded Anne Digby as a cheat and hypocrite; but John Evelyn regarded her as "a wise and noble person", even though some believed she had committed incestuous adultery with her husband's uncle, Henry Sidney.
Whatever the truth, their marriage did work and they learned to love one another, each becoming very much dependent on the other, so that seven children were born of the marriage. In their early years he
spent a great deal on Althorp and its gardens; and once Althorp was improved, he gave parties entertaining the Dukes of York and Monmouth.
These friendships assisted him in his political career and, in 1679 together with Essex and Halifax, he was in charge of government. Later the "triumvirate" changed to Godolphin, Hyde and again Sunderland.
The greatest mistake Sunderland made was when he came out in favour of the exclusion of the Duke of York, and in 1681 he was dismissed from office. Not only did his public life seem in tatters but he was
also desperately short of money. However, in January 1683 he was again appointed Secretary of State, which he remained for the rest of Charles II's reign. His saviour had been Louise de Kerouaille, the
king's mistress.
On the discovery of the Rye House Plot, amongst the guilty was his own uncle, Algernon Sidney, and Sunderland made no gesture of help or kindness during Algernon Sidney's long imprisonment and subsequent execution.
With James II everyone expected Sunderland to be out of favour, but he made himself indispensible. He was even willing to support James II's policy of a Catholic conversion for England, even to the extent
of declaring himself a Catholic in 1688. Within three years James II had lost all the goodwill shown him by England but Sunderland still assisted him on his determined if disastrous course.
James II rewarded this loyalty by sending Sunderland's son, Robert Spencer, on a trivial diplomatic mission to Modena. However, on the way in Paris, Robert indulged in such debaucheries that his health
gave way and he got only as far as Turin. From there he returned to Paris where he drank himself to death.
Sunderland's wife, a staunch Protestant, was shocked by his supposed conversion to Catholicism and turned to his uncle, Henry Sidney, causing the rumours about an affair. Sunderland then had a
nervous breakdown and was dismissed by James II.
On 5 November 1688, William III landed at Torbay while Sunderland lingered in London until a week later when he and his wife left for Holland. There he spent a short while in jail but was soon released on
orders of William III. Having found a house in Amsterdam they were son-an-heir went to the University. By this time Sunderland attended service in the Dutch Reformed Church.
Being regarded a traitor, he was forced to remain in exile until 1690 when, after an interview with William III, he was allowed to retire at Althorp. But before long he had returned as an advisor to
William III, so that from 1692 onwards he was regarded as "the minister behind the curtain". In April 1697 William III appointed him Lord Chamberlain as well as Lord Justice.
When his daughter-in-law died, Sunderland, with almost indecent haste, arranged a second marriage for his son with Lady Anne Churchill, daughter of the great Duke of Marlborough. Sunderland had
become a prematurely aged man being cared for by his devoted wife; he died only six months after King William III. The Dictionary of National Biography describes him as "the craftiest, most rapacious,
and most unscrupulous of all the politicians of his age".

Source: Leo van de Pas