The Fort Belvedere estate is situated in the extreme south end of Windsor Great Park in the parish of Egham, in the Borough of Runnymede in Surrey.

[2] Fort Belvedere was built 1750–1755, by Henry Flitcroft, for Prince William Augustus, Duke of Cumberland (1721–1765), younger son of George II and Queen Caroline, and was featured in an engravings in 1753 and 1754, where it was described as the "New building on Shrubb's Hill".

Sir Jeffrey Wyatville, who was responsible, under George IV, for the rebuilding of Windsor Castle, enlarged the house in 1828 at a proposed cost of £4000.

By 1910 the fort was occupied as a grace and favour residence by Sir Malcolm Murray, the Comptroller to Prince Arthur, Duke of Connaught and Strathearn.

[6] After the departure of Murray, the fort was described as suffering from "dust inches deep, splintered doors and sagging floors" in 1929.

[6] The ruins in the grounds can be seen from the shore of Virginia Water and are part of an ancient temple brought from Leptis Magna near Tripoli.

[9] Edward added modern conveniences at the fort, many of which were still rare in British homes, including bathrooms adjacent to nearly every room, a steam-room, showers, built-in cupboards and central heating.

[9][12] Notable interior decorators to work on the fort under Edward included Sybil Colefax, Lady Mendl, Maison Jansen, and Herman Schrijver.

[13][14] Edward and Wallis entertained most weekends at the house; guests present included 'courtiers and diplomats, American men of affairs and English Society, garnished with a sprinkling of statesmen, soldiers and sailors'.

His possessions from the fort were transferred to the Château de la Croë in the south of France (where he had named the sitting room "The Belvedere") in the spring of 1938, but many were damaged in transit.

Edward was informed in March 1940 that the fort was no longer in his possession as his warrant to occupy the grace and favour residence had expired on the termination of his reign and was not to be renewed by the present sovereign, his brother, now George VI.

Edward was greatly upset by this, writing in 1940 that "It is crystal clear that this proposed reserving of the Fort by the use of Crown Lands is nothing more than a piece of bluff, and the first excuse that the king has been able to find to deprive me of my right to occupy the place should I ever desire to do so ..." Edward believed that the incident was an example of his 'brother's failure to keep his word to me' after the fort had apparently been reserved for him if he should reside once more in England.

[13][20] Lascelles described the house as 'falling to pieces' at the beginning of his occupancy, and refurbished the fort, removing most traces of Edward's renovations in the process, except for the swimming pool and the battlements walk.

[21] The financial pressure following his divorce caused Gerald Lascelles to put his 78-year remainder of the lease up for sale through estate agents Savills in 1976.

[22] An advertisement for Fort Belvedere's lease listed the features of the fort as "Hexagonal central hall, fine drawing room, dining room, library, compact domestic quarters, 6 bedrooms, 5 bathrooms, arranged mainly in suites" and the expanse of the estate as "about 59 acres, of which 25 acres is freehold woodland".

[13] From the early 1980s until his death in 2021, the lease on Fort Belvedere has been held by the late Canadian billionaire retail magnate Galen Weston and his wife, Hilary.

The Westons have carried out extensive works on the fort, constructing a polo stud and doubling the size of the lake in the grounds.

A profusion of yew trees kept one side of the house in perpetual shadow, staining the wall with green acidulous mould.

[7] Prime Minister Baldwin complimented Edward on the beauty of the garden; commenting on the "silvery radiance of the birch trees and the delicacy of the autumn tints" in late 1936.

[32] Thirty-one brass cannon were moved to the north-facing crenelated terrace of the fort from nearby Cumberland Lodge in the early 19th century.