Castles were vital for the medieval period the Middle Ages that started with the arrival of William the Conqueror in 1066. He brought over architects that were very experienced in building castles, so the designs we see were imported from Europe.
Castles were places for lords to live in, but they also had to guard territory. Here you see a castle in Northumberland, and find out why it was sited where it was and see its main features.
For 1066 battle see: video gallery, top video