At core of ancient Slovak belief is the World Tree. The mythological symbol of the World Tree is a very strong one, and survived throughout Slavic folklore for many centuries after Christianization. Three levels of the universe are located on the tree. They are called Parv, Iav and Nav. The crown represents the heavenly deities, the trunk is the realm of mortals, and the roots of the tree stretch into the underworld.
In the crown of the tree is where the God of Fire - Svarog rules.
Below is the world Iav – the world of living creatures, the visible world. There rules the God of lightning and thunders – Perun.