Rhadamanthus. He goes on to describe other observations of how the residents occupy their time, using every opportunity to satirise both contemporary life and Greek mythology. Ptolemy used these islands as the reference for the measurement of geographical longitude and they continued to play the role of defining the prime meridian through the Middle Ages. See also Greek mythology in popular culture Hesperides Snake Island (Black Sea), "Isle of the Blessed" in Greek legend Annwn Brittia Elysium Mag Mell Tír na nÓg, the Isle of the Ever-Young Avalon, the Isle of the Blessed Aman, the "blessed realm" of Tolkien's works Buyan Macaronesia Vinland Great Ireland Saint Brendan's Island Notes Locations in Celtic mythology Locations in Greek mythology Mythological islands Death in Greek mythology Conceptions of heaven Macaronesia