Her Majesty's Royal Palace and Fortress

Her Majesty's Royal Palace and Fortress, more commonly known as the Tower of London, is a historic castle on the north bank of the River Thames in central London, England. It lies within the London Borough of Tower Hamlets, separated from the eastern edge of the City of London by the open space known as Tower Hill. It was founded towards the end of 1066 as part of the Norman Conquest of England. The Tower of London is often identified with the White Tower, the original keep built by William the Conqueror in 1078 and from which the castle derives its name. However, the Tower as a whole is a complex of several buildings set within two concentric rings of defensive walls and a moat. Although the Tower is popularly known today as a place of imprisonment, and was used as such from as early as 1100, that was not its primary purpose. Early in its history, the Tower was a grand palace, serving as a royal residence. The castle underwent several expansions, especially under Kings Richard the Lionheart, Henry III, and Edward I, resulting in its current general layout in the 13th century.