It is thought that the mound on which the keep stands was a site used by the ancient Britons, and that in Anglian times, there was a stronghold on the site held by Mildred, son of Ackman.
The mound where the keep is situated is thought to have been used by the ancient Britons, and during the Anglian period, it housed a stronghold controlled by Mildred, the son of Ackman, indicating a historical connection between the site and a prominent figure.