Denham became a
Member of Parliament for
Old Sarum in 1661, became a
Fellow of the Royal Society on 20 May 1663, and became a
Knight of the Bath. He received substantial grants of land in compensation for his forfeited estates. He built or commissioned the original
Burlington House in
Piccadilly in about 1665. After the Restoration Denham became
Surveyor of the King's Works, probably due to his earlier political services rather than for any aptitude as an
architect.
John Webb, who, as
Inigo Jones's deputy undoubtedly had the competence to have served in the post, complained that "though Mr. Denham may, as most gentry, have some knowledge of the theory of architecture, he can have none of the practice and must employ another". There is no evidence that he personally designed any buildings, although he seems to have been a competent administrator; he may, however, have played some part in the design of his own home, Burlington House. John Webb was appointed Denham's deputy by 1664 and did Denham's work at
Greenwich (from 1666) and elsewhere.
Second marriage to Margaret Brooke Denham in 1665 made an unhappy second marriage to Margaret Brooke, a beautiful young woman almost thirty years his junior, who conducted a very public affair with the future King
James II. To her husband's mortification, she insisted on being acknowledged publicly as a Royal mistress, saying that she would not, unlike her predecessor Goditha Price (daughter of Sir
Herbert Price, the
Master of the Household), "go up and down the back stairs, but would be owned publicly". When she died in January 1667 after a short illness, Denham was rumoured, by
Samuel Pepys among others, to have murdered her by giving her a poisoned cup of
chocolate, although the
autopsy found no trace of
poison, and she had been seriously ill the previous year. In any case, rumour named several other possible poisoners, including James, his wife
Anne Hyde and his sister-in-law, Lady Rochester.
Last years, death, and children His last years were clouded by
dementia. He had long been rumoured to be insane, a condition generally attributed to his scandalous marriage, and later the hostility of the London public, which regarded him as a murderer, and he became a virtual recluse. With Denham's increasing mental incapacity, Charles II requested in March 1669 that
Christopher Wren be appointed Denham's "sole deputy"; Wren succeeded him as King's Surveyor upon his death two weeks later. Denham was buried in
Poets' Corner of
Westminster Abbey. The public suspicion about his role in his wife's death continued to the end of his life. He was survived by his daughters, Elizabeth, who married Sir Thomas Arden Price in 1675 but died childless, and Anne, who married Sir William Morley of Halnaker, by whom she had two sons who died young and a daughter Mary, who married
James Stanley, 10th Earl of Derby, but had no surviving issue. ==Works==