How and Why did the Norman conquerors build castles?
The main reason William the Conquerer built castles in England was so that he could control rebellions and keep his people safe. Also, he built them as bases for tax collection. The Normans built the early castles by digging a deep circular ditch, and piling up the earth taken from the ditch into the centre. That became the motte. Sometimes, the motte began as a natural hill, which was shaped into a usable mound and surrounded by a ditch. You can read the rest here from the sources I’ve provided.
