The earliest castle would have resembled the depiction of a motte and bailey fortress below. There was a motte, which was a mound or hill with a wooden watchtower on top. On top of the hills of the Belvoir Ridge, with views stretching for miles across the Nottinghamshire countryside, this is an ideal location for a castle. The term "motte" comes from the Old English word mōd, which means "hill." The earliest evidence of human settlement at Langar dates back to around 730 AD when the area was inhabited by Celtic tribes. In the year 1022, William the Conqueror ordered that a castle be built within the boundaries of present-day Leicestershire and Nottinghamshire to control rising tides of crime throughout his kingdom. The original timber castle was replaced in stone about 15 years later. This is the same time as similar castles were being constructed across England by Edward I and Edward II. Langar Castle was initially designed as a prison, but it also served as a place of refuge for other people in need. The bailiff of the castle made sure that anyone requesting sanctuary was given safe conduct until peace was restored. If they were a danger to others once they had been pardoned, then they could be returned to prison. Early records show that there were almost 50 prisoners held at Langar Castle at one time or another between 1066 and 1547, including two kings: Henry III and Charles VI of France.