See:
TF4153 : Kings of the Castle: Kings Hill Motte and Bailey castle earthworks and
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The motte is a mound, the strong point of the castle where the tower or keep stood, and the bailey is the defended flat area below the mound, for the domestic buildings.
This form of castle was common in England between the late 11th and early 12th century. A Saxon monk wrote at the time, that William the Conqueror "caused castles to be built, which were a sore burden to the poor".
The Wrangle estate was quite important, and the castle would have been its centre. The King in the name was probably James I, who acquired the site in the 17th century.
Here the motte is on the north, and is the roughly circular raised platform.
King's Hill was a lot bigger than it looks today and records from 1911 show that it had a large complex of earthworks around the motte and bailey which may represent outbuildings or animal pens. In its day the castle would have looked very formidable, but the mound and ramparts have eroded, and the strong wooden walls have rotted away with the passage of time.