The 'Vlie' or 'Vliestroom' is the seaway between the
Dutch islands of
Vlieland and
Terschelling. The Vlie was the
estuary of the river
IJssel in medieval times. In
1666 the
English Admiral
Robert Holmes burnt a Dutch merchant fleet of 150 ships (
Holmes's Bonfire), that had taken refuge in the Vlie, mistakenly supposing the English could never find their way through the treacherous
shoals, so typical for the coastal waters there. Today it's still possible to reach the port of
Harlingen by way of the Vlie.
It is often supposed that the old Roman name for the lake that later would become the
Zuiderzee: ''Lacus Flevo'', is etymologically related to the name "Vlie" and that perhaps Vlie was once the name of the entire lake and the big river that flowed out of it. In the 13th century large floods widened the estuary and destroyed much of the peat land behind, creating a continuous area of sand and
mudflats connecting the sea to the enlarged inland lake and obscuring the flow of the river. When the
Afsluitdijk was created, the old streambed from the river to the sea was interrupted.