In the 1820s, George IV asked his architect, John Nash, to build a state palace. Nash added wings at the front of the house and extended the back.
Queen Victoria was the first sovereign to take up residence just three weeks after her accession on July 13, 1837, and the Palace was further extended during her reign.
King George VI and Queen Elizabeth (now the Queen Mother) brought up the Princesses Elizabeth and Margaret there and, during the Second World War, the royal couple decided to continue to live in it despite the Blitz.
Windsor Castle, fully restored following the 1992 blaze which gutted the north-east section of the castle, including St George's Hall and the Grand Reception Room, has been an official residence of sovereigns for more than 800 years.
The original castle was built by William the Conqueror in about 1070 as one of a chain of strongholds to control the area around London. It was rebuilt and enlarged over the centuries, although the outline still follows the shape of the original earthwork.
In 1215, King John rode reluctantly from the castle to nearby Runnymede to set his seal on Magna Carta.
Earlier, Henry I was the first monarch to make it a royal house when in 1121 he married his second wife, Adelaide of Louvain, in a chapel within the castle.
Two kings were born in the castle. One, Edward III (1327-77) founded the Order of the Garter, while the other, Henry VI (1422-61), founded Eton College.
Edward VIII, briefly king in 1936, was the only sovereign never to have spent a night in the castle as monarch.
