Richborough was one of the longest Roman-occupied sites in Britain, with history stretching from the Claudian invasion of Britain in 43 AD to the Roman departure almost 4 centuries later. During its long history Richborough transformed on several occasions. From military base to prosperous port town, from supply base to Saxon shore fort. And the archaeology left behind is testament to Richborough's importance in Roman times. English Heritage's Andrew Roberts takes Tristan Hughes on a tour of Richborough's Roman remains, talking through the site's long and complex history.