The world's largest functioning residential palace is the Istana Nurul Iman in Brunei, with 200,000 square metres (2,200,000 sq ft) of floor space and contains 1,788 rooms.
It served as the principal residence of the monarch until 1522, when Henry VIII moved his court to the newly acquired Palace of Whitehall.
The palace which now stands on the site was designed specifically for parliamentary use, however it is the property of the monarch in right of the Crown and retains its status as a royal residence.
However, the modern Hermitage Museum complex, centered on the Winter Palace, contains 1,978,622 square feet (183,820 m2) of floorspace.
While numerous claimants under the various measurements can be recognized, to be considered for the Guinness World Record the palace must have once been intended for use as a royal residence.
This is controversial as the definition of a palace is the official residence of a sovereign, chief of state (as a monarch or a president), archbishop, bishop.
[14] The Istana Nurul Iman, with 2,152,782 square feet (200,000 m2) of floorspace,[15] holds the title as the "world's largest residential palace" held in Brunei.
The size of the palace complex is unknown, but it contained a T-shaped artificial lake covering an area of at least 2 km2 (3.6 km2 according to some estimates).
[19][20] The Roman emperor Hadrian's Villa at Tivoli, Italy was a complex of over 30 buildings constructed between 118 and the 130s AD, covering an area of at least 250 acres (1,000,000 square metres (11,000,000 sq ft)) of which much is still unexcavated.
The complex included palaces, several thermae, theatre, temples, libraries, state rooms, and quarters for courtiers, praetorians, and slaves.
[21][22][23] When Roman emperor Nero's "Golden House" (Domus Aurea) was built after the great fire of AD 64, the buildings covered up to 300 acres (1,214,056 square metres (13,067,990 sq ft)).
[24][25] In 200 BC, the Weiyang Palace was built at the request of the Emperor Gaozu of Han, under the supervision of his prime minister, Xiao He.
He ordered the construction of the summer palace for his retired father, the Emperor Gaozu of Tang, as an act of filial piety.
Wu Zetian commissioned the court architect Yan Liben to design the palace in 660, and construction commenced once again in 662.
Al-Mu'tasim built the 125 ha (309 acres) Dar al-Khilafa in 836, as the main palace complex and residence of the Caliphs, serving this function until its abandonment in 892.
The former was the public palace in which the Caliph sat in audience on Mondays and Thursdays, where al-Musta'in was given allegiance and al-Muhtadi held the Mazalim court.
[27] Caliph al-Mutawakkil sought to outdo his predecessors and was a prolific builder, spending some 13,525,000 dinars (276,045,250 dirhams) in total and doubling the size of the city.
But only a year and a half later, on 11 December 861 it served as the place of his assassination at the hands of his Turkish guard and start of the Anarchy at Samarra.