Built in the Motte and Bailey style, construction began around the 11th Century under William The Conqueror. Originally designed to establish Norman dominance over the region, Windsor Castle occupied a strategically important position in The Thames River. It is composed of 3 Wards surround by a central mound (Motte). As time progressed, the original wooden structures were replaced by stone. Besieged during The First Baron's War (13th Century), it saw additional military history during The English Civil War. It served as headquarters for Parliamentarian forces and King Charles I was kept prisoner there. King Henry III built a luxurious palace within Windsor's fortifications. The opulence of the grounds would continue with Edward III, who too added to the grounds and buildings. Historians consider this Windsor's "Grand Period" or renovations (which were considered some of the most expensive of any Middle Ages Kingdom). During The Tudor Period, King Henry VIII and his daughter Queen Elizabeth I - would use Windsor as a center for diplomatic exchanges and visits. Although much of the castle suffered under Parliamentarian control, after The Restoration, Charles II spent large amounts to restore it yet again. Sitting mostly in neglect in the 18th Century, King George IV began new renovations. Queen Victoria saw to it that Windsor regained it status as a diplomatic center again. The castle is currently the weekend residence for England's serving monarch, Queen Elizabeth II.