The Tower of London was founded in 1078 when William the Conqueror ordered the White Tower to be built inside the south-east angle of the City walls, adjacent to the Thames. This was as much to protect the Normans from the people of the City of London as to protect London from outside invaders. William ordered the Tower to be built of Caen stone, which he had specially imported from France.
The Tower's primary function was a fortress, a royal palace, and a prison (particularly for high status and royal prisoners, such as the Princes in the Tower and the future Queen Elizabeth I). It has also served as a place of execution and torture, an armoury, a treasury, a zoo, a mint, a public records office, an observatory, and since 1303, the home of the Crown Jewels of the United Kingdom.
Ravens have called the Tower home for several centuries, and legend has it that if the ravens ever leave the Tower of London, the White Tower, the Monarchy, and the entire Kingdom would fall.