On his return he was wrecked on the holy island of Fosite (Heligoland), where his disregard of the pagan superstition nearly cost him his life.
In 1402, after the defeat of the pirates off Heligoland by the fleet of Hamburg, Emden was besieged, but it was not reduced by Hamburg, with the aid of Edzard Cirksena of Greetsyl, until 1431.
A closer investigation of the numerous long, narrow banks which lie off the Flemish coast and the Thames estuary shows that they are composed of fragments of rock abraded and transported by tidal currents and storms in the same way that the chalk and limestone worn off from the eastern continuation of the island of Heligoland during the last two centuries has been reduced to the coarse gravel of the off-lying Dune.
The generally accepted derivation of Heligoland (or Helgoland) from Heiligeland, i.e.
Such doubtless was Fosite, to whom Heligoland was sacred.