Syon House & Conservatory

Syon House, once known as Northumberland House before its demolition, has long been a significant landmark in central London, with its eclectic interior designed by the renowned architect Robert Adam in the 1760s.

The house derives its name from Syon Abbey, a medieval monastery of the Bridgettine Order founded in 1415 by King Henry V. Initially located on a nearby site, the abbey moved to its current location in 1431, becoming one of the wealthiest nunneries in England. According to local legend, a ley tunnel once connected the monks of Sheen to the nunnery at Syon. However, the abbey’s fate changed in 1539 when it was closed during the Dissolution of the Monasteries, and its community was expelled.

After its dissolution, Syon briefly became Crown property before being leased to the 1st Duke of Somerset, who transformed it into a grand residence in the Italian Renaissance style. The house holds a storied history, including serving as the site of imprisonment of Henry VIII’s fifth wife, Catherine Howard, in 1541 before her execution in 1542. The following year, Henry VIII's coffin rested at Syon House for one night before its final journey to St George's Chapel in Windsor.

In 1553, Lady Jane Grey was formally notified at Syon House that she was the heir to the throne following the death of King Edward VI. A delegation led by John Dudley and members of the Privy Council met with her in the Long Gallery to deliver the news.

Though there were plans in 1557 to return Syon to its Catholic roots, this never materialized due to Elizabeth I's ascension to the throne. The house was acquired by Henry Percy, 9th Earl of Northumberland, in 1594 and has remained in his family ever since.

Syon House also holds a unique place in the history of astronomy. In 1609, Thomas Harriot made the first known telescopic drawings of the moon on its grounds, months before Galileo's famous observations. A plaque now marks the site of these groundbreaking observations.

During the late 17th century, Syon became a refuge for Princess Anne after a falling out with her sister, Queen Mary II. Anne gave birth to a stillborn child there in 1692, after which Queen Mary visited, only to leave in anger when Anne refused to dismiss her close friend, the Countess of Marlborough.

The 18th century saw significant transformations at Syon House under the direction of Hugh Percy, 1st Duke of Northumberland, who commissioned Robert Adam and landscape designer Capability Brown to redesign the house and its estate. Adam's work began in 1762, introducing a suite of staterooms that remain largely as they were initially designed. Adam’s eclectic style, which emerged at Syon House, blends Neoclassical, Roman, Baroque, and Gothic elements, along with motifs inspired by Pompeii.

The house underwent further renovations in the 1820s and 1860s, with additions like Renaissance-style plaster ceilings and a remodelling of the north range. Syon Park, a 200-acre expanse bordering the Thames, was designed by Capability Brown but retains a 19th-century character. The Great Conservatory, which I have illustrated here, was completed in 1827 and was the first large-scale conservatory made from metal and glass. It is now Grade I listed.

Syon House is open to the public, and its grounds have hosted several attractions, including the London Butterfly House and the Heritage Motor Museum. It remains a popular filming location, featured in productions like Gosford Park, Killing Eve, and Bridgerton.

Syon Park is also a Site of Special Scientific Interest, with ongoing archaeological excavations uncovering its rich history, including the remains of a Roman village. Today, the Percy family maintains Syon House and its estate.