In Iron Age Britain around 700 BC, a settlement on the Head was established; also around this time, the headland was cut off from the mainland by the construction of two banks and ditches called the Double Dykes, similar to those found at Maiden Castle. The earthworks consisted of an inner bank three metres high, with a ditch three and a half metres deep. An outer ditch six metres wide and two metres in depth is now obscured due to wind-blown deposits of sand and a gradual silting process. These defences turned Hengistbury Head into a fortified settlement area which seems to have grown over succeeding centuries until it became an important port. The Iron Age port at Hengistbury Head forms a final site in a small chain of fortified earthworks, starting from Hambledon Hill, and also including Hod Hill, Spetisbury Rings, Buzbury Rings, Badbury Rings and Dudsbury Camp.