This is the most common
graphical structure representing Thor's hammer Mjölner, a symbol from the time of the
old Aesir religion, whose last approximately 400 years coincided with
the Viking era. Tor, son of Oden (anglosaxon Woden), was the second
highest of the Nordic gods. He is often depicted slammering over the
clouds of the heavens in his chariot drawn by two he-goats. Thunder
was known as Thordön, that is the roar of Thor.
Mjölner appears engraved on stones, or hammered or cast in metal for use as an amulet.