William Fitzwilliam Third Earl of Milton
From "How The City Has Changed" by H.F. Tebbs (1975), a collection of articles originally written in the Peterborough Standard (predecessor to the Herald and Post).
"This is the remains (referring to the picture) of the Sixteenth century Dogsthorpe Manor. The hamlet which was apparently in the hands of a Saxon called Dodde is much older and took its name Doddesthorpe from him.
The Manor house which had been a grange of the Abbey was bought by William Fitzwilliam as his home in 1578. It included 286 acres of land which had to supply his household beyond paying its own expenses.
William was a courtier with some duties under Queen Elizabeth as a Gentleman Pensioner of the household and as Member for Peterborough in the Parliaments of 1573, 1584/5 and 1586/7. His wife Winnifred, was the daughter of Sir Walter Mildmay the financial wizard of the age who designed the Queen's new mint and re-organised the coinage to replace that which had become very debased.
Dogsthorpe had always been a sheep and cattle raising farm. It had good grazing and grew enough good hay to keep calves in the winter. After 1603 when William retired from court, sheep also became more profitable and he seems to have concentrated the area on sheep farming.
His son, who became the 1st Baron Fitzwilliam, overspent and had to sell the farm in 1633."
However information from the National Archives give William's dates as 1526 to 1599, and gives more information about his roles as Lord Justice in the early 1560s and Lord Deputy, 1571-1575 and 1588-1594.
There is much more information about the early Fitzwilliams at WentworthVillage.net/history.shtml this confirms the dates 1526 - 1599. His son also William Fitzwilliam (4th Earl) died in 1615, both are buried at Marholm, Peterborough. This website has the dates for the next generation (5th Earl) as 1620 - 1634, the family tree shows the father dying in 1615 and the son being born in 1620! The son William Fitzwilliam was the first Baron Fitzwilliam of Liffer Co. Donegal, quite an acheivement for someone who supposedly only lived 14 years.
I subsequently found via Google Book Search "Promotions to the Peerage 1620", which states "By patent dated Westminster, December 1, William Fitzwilliam, of Milton, Northamptonshire, Esquire, was created Lord Fitzwilliam of Liffer, alias Lifford, in the County of Donegal, in the Peerage of Ireland." Which suggests 1620 was the date of his peerage, not his birth.
From Peterborough City Council website I learnt that "After 1618, and for the next three or four generations, the family's income came from less lucrative sources, principally the agricultural management of their estates, especially grazing sheep on enclosed land, and from rents from their tenants." and "Gaynes Park,an estate in Essex, was sold in 1636". Which appears to support H.F. Tebbs reason for Dosthorpe Manor being sold.
William Sly
William Sly died in September 1697, I obtained the following details from his will which is online in the National Archive. He left estates both freehold and leasehold in Dogsthorpe, Eastfield, and Newark to his son, also named William Sly, who was not yet 21. His loving wife received the furniture of the best chambers, some plates, spoons and a silver cup.
If his son should die before his 21st birthday the estate was to be split between the elder William's three sisters, Anne Miller wife of William Miller of Thorney Abbey, Susanna Miller wife of William Miller of Stibbington, and Mary Sly a spinster who lived in Dogsthorpe.
Sly's Farm can be seen on the 1889 map, it would be interesting to find out if the family lived there for another 200 years or if it was just the name which remained.