 Later Ptolemy incorrectly identified the Blessed Islands with the Canaries and since it was known that the Blessed Islands were at the antipodes relative to the eastern part of China, Ptolemy made ends meet by erroneously enlarging the longitude of all known places, and shrinking the width of a degree of longitude (500 instead of 700 stadia).With this correction Lucio Russo manages to pinpoint the position of the mythical Thule, reached in the 4th century BC by explorer Pytheas, on the coast of Greenland.In addition he sheds a new light on an obscure sentence of Pliny according to which Hipparchus would have enlarged the ecumene (the known world) by 26,000 stadia.