Five years later, when King Henry VIII died, his coffin, surmounted by a jewelled effigy, rested at Syon House for one night before the procession continued to his burial place in St George's Chapel, Windsor.

Lady Jane Grey received formal notification at Syon House on Sunday, 9 July 1553 that she was King Edward VI's heir to the throne.

A delegation consisting of Dudley and members of the Privy Council together with their wives are said by tradition to have met with Jane in what is now the Long Gallery to officially convey the news to her.

[6] In 1609, Thomas Harriot was working at Syon when he made the first ever use of the newly invented telescope to make astronomical drawings of the moon on 26 June, several months ahead of Galileo's observations.

[8] In 1951, Syon House was opened to the public for the first time under Hugh Percy, 10th Duke of Northumberland and his wife Elizabeth.

[2] Adam's plan of Syon House included a complete set of rooms on the main floor, a domed rotunda with a circular inner colonnade meant for the main courtyard ('meant for' meaning that this rotunda was not built due to a lack of funds), five main rooms on the west, east and south side of the building, a pillared ante-room famous for its colour,[13] a Great Hall, a grand staircase (though not built as grand as originally designed) and a Long Gallery stretching 136 feet long.

Adam added detailed marble chimneypieces, shuttering doors and doorways in the Drawing Room, along with fluted columns with Corinthian capitals.

[17] Henry Percy, 11th Duke of Northumberland, who was head of the family from 1988 to 1995, was noted for planting many trees in the grounds of Syon.

The London Butterfly House was based in the grounds of Syon Park from 1981 until its closure on 28 October 2007 due to Ralph Percy, 12th Duke of Northumberland's plans to build a hotel complex on the land.

[18][19][20] Also based in the grounds of Syon Park was the Heritage Motor Museum, a collection of vintage cars, which was also founded in 1981.

Owing to a major increase in the number of vehicles acquired, in 1993 the museum closed and its collection was transferred to the Heritage Motor Centre at Gaydon in Warwickshire.

[21] Before that, Syon House was host to the London Transport Collection after the closure of the Clapham museum and prior to its move to Covent Garden in 1980.

[22] In 2002 an annual archaeological dig was initiated, originally by the Channel 4 television Time Team programme, to excavate the remains of the lost abbey.

[12] In November 2010, the results from an archaeological dig made two years before on the site of the new hotel were reported, with the excavations uncovering the remains of a Roman village that existed in what was then the rural outskirts of Londinium.

[26] Syon House and its grounds have frequently been used as locations for filming including: Gosford Park,[27] King Ralph,[28] Emma,[29] The Avengers,[30] Killing Eve,[31] Belgravia[32] and Bridgerton.