The castle is an impressive Iron Age hill fort, once protected by timber walls on top of the surviving banks and ditches. It is likely that the tribe who created the White Horse once lived within this hill fort. The entrance to the hill fort was via the Northwest, protected by an earthen passageway that would have been further protected by wood. The castle was excavated in 1850 when evidence of the wooden structure was found, along with an Iron Age coin of the Dobunni tribe.
Some researchers believe that the castle marks the site of the battle of Badon, Arthur's great victory over the Saxons. This is probably due to the important strategic position of the castle close to the Ridgeway. There is little evidence to suggest this is the case.
For access see White Horse.