Sir Orfeo as being a parallel dimension to the everyday world rather than the Land of the Dead as in the Greek myth of Orpheus and Eurydice. The ability to move between one world and the other distinguishes the tale as told in its various British versions such as "Sir Orfeo" and the Shetland ballad "King Orfeo" where the captors are envisaged as inhabitants of a parallel fairy domain rather than as the infernal region of the Dead ruled over by Hades as in the Greek myth. Katharine Briggs sees the tale as related in British folk narratives as being equally influenced
Eridanos (river of Hades) with the excavations for construction of the Athens Metro. Eridanos is the name that has been applied by geologists to a river which flowed where the Baltic Sea is now, a river system also known simply as the "Baltic River System". Eridanos (river of Hades) The river Eridanos or Eridanus (; , "Amber") is a river in northern Europe mentioned in Greek mythology and historiography. Hesiod, in the "Theogony," calls it "deep-eddying Eridanos" in his list of rivers, the offspring of Tethys and Oceanus. Herodotus suspects the word "Eridanos" to be essentially Greek in character, and notably forged by some