An example of zoroastrianism . The figure on the right is Ohrmazd , the principle of truth and light , riding on horseback who tramples on Ahriman ' s ( The zoroasrian devil ) snake covered head . Zoroastrians believed the perpetual struggle between the two would end in the triumph of Ohrmazd . On the left a Persian King tramples an enemy. From a rock relief at Naqshi - Rustem