Berkshire (pron.: // or //, abbreviated Berks) is a county of south east England, located to the west of London. It has also been known as the Royal County of Berkshire since at least the 19th century because of the presence of Windsor Castle and was recognised as such by the Queen in 1957 and letters patent issued in 1974. Berkshire is a county of historic origin and is currently both a ceremonial county and a non-metropolitan county without a county council. Berkshire County Council was the main county governance from 1889 to 1998, except for the separately administered County Borough of Reading. In 1974 the towns of Abingdon, Didcot and Wantage were transferred to Oxfordshire, Slough was gained from Buckinghamshire, and the separate administration of Reading ended. Since 1998 Berkshire has been governed by the six unitary authorities of Bracknell Forest, Reading, Slough, West Berkshire, Windsor and Maidenhead and Wokingham. It borders the counties of Oxfordshire, Buckinghamshire, Greater London, Surrey, Wiltshire and Hampshire.
Windsor Castle is a royal residence at Windsor in the English county of Berkshire. The castle is notable for its long association with the British royal family and for its architecture. The original castle was built in the 11th century after the Norman invasion by William the Conqueror. Since the time of Henry I, it has been used by succeeding monarchs and it is the longest-occupied palace in Europe. The castle's lavish, early 19th-century State Apartments are architecturally significant, described by 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". The castle includes the 15th-century St George's Chapel, considered by historian John Robinson to be "one of the supreme achievements of English Perpendicular Gothic" design. More than five hundred people live and work in Windsor Castle.
Originally designed to protect Norman dominance around the outskirts of London, and to oversee a strategically important part of the River Thames, Windsor Castle was built as a motte and bailey, with three wards surrounding a central mound. Gradually replaced with stone fortifications, the castle withstood a prolonged siege during the First Barons' War at the start of the 13th century. Henry III built a luxurious royal palace within the castle during the middle of the century, and Edward III went further, rebuilding the palace to produce an even grander set of buildings in what would become "the most expensive secular building project of the entire Middle Ages in England". Edward's core design lasted through the Tudor period, during which Henry VIII and Elizabeth I made increasing use of the castle as a royal court and centre for diplomatic entertainment.