On 14 February 1786, in London, Lord Petre married Mary Bridget Howard (29 September 1767 – 30 May 1843), sister of the 12th Duke of Norfolk.
They were the parents of seven children; By the beginning of the 19th century, the Rector was paying the pensioners of the almshouses 6s 8d each month (about £13 today), £1 annually for the purchase of firewood, and 12s each year for the stipulated livery of the Charity.
had purchased Woburn Farm, alias Cocks lands, consisting of about 25 acres (100,000 m2), in 1735 from a Mrs. Hornby.
The other view is more wooded, and from this, the bold arch of Walton Bridge is a conspicuous object equally singular and noble.
By her will, dated 25 April 1771, she devised her seat, consisting of a 'capital messuage', large garden, and an ornamented farm used therewith, then in her own occupation, to Thomas Berney Bramston and John Maire Esq., on trust to settle the same on her esteemed friend and kinsman Robert Edward lord Petre for life, and thence to heirs male.