Windsor Castle is a royal residence at Windsor in the English county of Berkshire. It is notable for its long association with the English and later British royal family and for its architecture.
The original castle was built in the 11th century after the Norman invasion of England by William the Conqueror. Since the time of Henry I, it has been used by the reigning monarch and is the longest-occupied palace in Europe.
The castle's lavish early 19th-century State Apartments were described by early 20th century art historian Hugh Roberts as "a superb and unrivalled sequence of rooms widely regarded as the finest and most complete expression of later Georgian taste".
Inside the castle walls is the 15th-century St George's Chapel, considered by the historian John Martin Robinson to be "one of the supreme achievements of English Perpendicular Gothic" design.
Windsor Castle survived the tumultuous period of the English Civil War, when it was used as a military headquarters by Parliamentary forces and a prison for Charles I. At the Restoration of the monarchy in 1660, Charles II rebuilt much of Windsor Castle with the help of the architect Hugh May, creating a set of extravagant Baroque interiors that are still admired.
After a period of neglect during the 18th century, George III and George IV renovated and rebuilt Charles II's palace at colossal expense, producing the current design of the State Apartments, full of Rococo, Gothic and Baroque furnishings.
According to en.wikipedia