Its name comes from its relationship to the land of the Frisians (see Frisia). They live directly to the south of the "North Sea", and to the west of the "East Sea" ("Oostzee", the Baltic Sea), the former "South Sea" ("Zuiderzee", today's IJsselmeer) and the today reclaimed "Middle Sea" ("Middelzee"). But the spread of the name could also be from the view of the cities of the Hanseatic League. Some of its main cities, like Lübeck, Bremen or Hamburg had the same view.