 Perun was also related to an archaic form of astronomy – the Pole star was called Perun's eye and countless Slavic and Hungarian astronomers continued this tradition – most known ones are Nicolaus Copernicus, and Franz Xaver von Zach.In Slavic mythology, much like in Norse and Baltic mythologies, the world was represented by a sacred tree, usually an oak, whose branches and trunk represented the living world of heavens and mortals, whilst its roots represented the underworld, i.e.the realm of the dead.