only dates to the 5th century, later than the channel defences of the late 3rd and 4th century associated with the Saxon Shore.

The other interpretation holds that the forts fulfilled a coastal defence role against seaborne invaders, mostly Saxons and Franks, and acted as bases for the naval units operating against them. This view is reinforced by the parallel chain of fortifications across the Channel on the northern coasts of Gaul, which complemented the British