This small fort was first occupied during the 1st century BC when a wide rampart and external v-shaped ditch was erected across the neck of the promontory to enclose an area of 4½ acres (1.8ha).
Occupancy continued throughout the Romano British period, during which the bank was raised in height and two more external banks added. The rocks of the hill beneath the fort are rich in iron-ore and during Roman times this was an important source of the metal in the area. One Roman mine shaft may still be explored via a trap-door in the hillside beside the Adam & Eve statue, behind which there is a 50 foot (c.15m) long shaft running obliquely under the fort.
During the fourth-century the southern half of the site was taken over by a Romano-British temple complex. The religious buildings consisted of a substantial guest-house, a bath suite and a temple dedicated to Nodens, the iron-age god of hunting and healing.