 The map bears inscription next to Lagarfljót stating that "In this lake appears a large serpent ("In hoc lacu est anguis insolitæ magnitudinis")" which are a menace to the inhabitants and appear when some memorable event is imminent".A briefer inscription noting only a serpent of great size is found on a Mercator map of 1595.Bishop 's "Qualiscunque descriptio Islandiae" (ca.