A sequence of fortifications, believed to have been constructed in the late 3rd century against raids by the Saxons of Germany, Holland and Denmark, stretches from north Norfolk to Portchester.

Some, like Portchester and Burgh Castle, have substantial remains, many have later structures within or over them. Some (like Walton Castle) have more or less disappeared into the sea, and at Dover the construction of the fort wall resulted in the preservation of an earlier house with wall-paintings - ‘Britain’s buried Pompeii’.

We visit the sites of all the identified forts, around the changing sea-scapes of East Anglia and the south-east, and also trace the Roman presence in this part of the world and its replacement by the very different culture of the Saxons.