What is "ictis"

Ictis, or Iktin, is or was an island described as a tin trading centre in the Bibliotheca historica of the Sicilian-Greek historian Diodorus Siculus, writing in the first century BC.

While Ictis is widely accepted to have been an island somewhere off the southern coast of what is now England, scholars continue to debate its precise location. Candidates include St Michael's Mount and Looe Island off the coast of Cornwall, the Mount Batten peninsula in Devon, and the Isle of Wight further to the east.