A deer bank was a huge ditch and bank systems built in Medieval times by the owners of woods in order to prevent the
passage of deer and cattle over the boundary. During the 12th and 13th centuries Norsey Wood was part of the Forest of Essex, which during these
centuries was Royal Forest - the King's hunting ground, which was protected by Forest Law. Under Forest Law landowners could only hunt or take wood
out of the forest with the King's permission. This was done by licence. Crondon Park during this same period belonged to the Bishop of London.
Another name for a deer bank was a deer leap.