

Gradually replaced with stone fortifications, the castle withstood a prolonged siege during the First Barons' War at the start of the 13th century.

Originally designed to project Norman dominance around the outskirts of London and 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. 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. The castle's lavish early 19th-century state apartments were described by the 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". Since the time of Henry I (who reigned 1100–1135), it has been used by the reigning monarch and is the longest-occupied palace in Europe. The original castle was built in the 11th century, after the Norman invasion of England by William the Conqueror. It is strongly associated with the English and succeeding British royal family, and embodies almost a millennium of architectural history. Windsor Castle is a royal residence at Windsor in the English county of Berkshire. The Royal Estate, Windsor: Windsor Castle and Home Park National Register of Historic Parks and Gardens
