Some of the major sea-ports of medieval Europe still continue and flourish as ports; medieval Hamwic became the container port of Southampton. Some have faded away, as their harbours have silted or the pattern of trade has moved away. Some have so completely failed that certain knowledge of what and where they has been forgotten. Chief of these lost ports of Europe is Quentovic, whose site has been sought in northern France and is here defined in the Canche valley, south of Boulogne.