In Western unicorn lore, the Lion and the Unicorn have traditionally been considered rivals and natural enemies destined to fight. But in all of the tales of this rivalry, there is no suggestion that they represent good and evil. At best they are complimentary, at worst they are incompatible. At times both have been called the lord of all beasts, but their styles of sovereignty are totally different. The extrovert and the introvert, one fiery and one cool, they represent opposite principles which are fine in and of themselves so long as they are not in competition.

There is a tale common throughout the ancient Middle East which tells how the Lion and the Unicorn chased each other across the heavens at the dawn of time. For fourteen years the Lion chased after the Unicorn through the stars, but it pulled away and circled round. Then for the next fourteen years it was the Unicorn who chased the Lion, slowly but steadily gaining, closing the distance between them with its horn growing ever more sharp and deadly. In despair the Lion came to earth and plunged into a forest with the Unicorn close behind, its horn lowered for the kill. Suddenly an enormous tree stood in their path. The Unicorn, seeing the danger too late, charged straight on and buried its horn to the hilt in the tree's trunk. While the Unicorn was thus pinned, the Lion crept up from behind and devoured him.

There are variations of this tale in different cultures around the world. Some versions reverse the outcome—the Unicorn impales the Lion before he reaches the tree.

This reversal may be a clue to the real meaning of the story. It's a drama we witness in the heavens every month:  the new moon chases the sun across the sky, falling ever further behind but waxing as it does so, until finally it is charging towards the sun from the opposite direction, its crescent horn growing ever more slender and sharp. Then the sun devours it and for a few days and nights the moon disappears from the sky—to await rebirth. On the occasion of a solar eclipse, the tables are turned and it is the sun that briefly dies in the sky.

The Lion is a well established solar symbol in astrology. The Unicorn is not quite as widely accepted as a symbol for the moon. This connection may be due in part to its association in pagan times in certain lands with cults of the moon. However it originated, the association was commonly accepted by the time of England's James I (1567-1625).

When James VI of Scotland ascended to the throne of England and Ireland as King James I in 1603, a new royal coat of arms had to be designed to combine those of Scotland and England. Since at that time the Scottish coat of arms featured two unicorns and England's two lions, the decision was made to use one unicorn and one lion. In his written comments about the heraldic Unicorn, James spelled out this astrological association. He said that in heraldic terms the Lion and Unicorn not only represented the union of two formerly warring nations, but showed that the new order of things was supported by the balanced forces of nature, sun and moon in harmony.

Symbolically, the Lion represents the urge to impose one's idea of order upon the world, while the Unicorn exemplifies the drive to bring harmony through insight and understanding. Their effects are often identical, but their different approaches tend to promote strife. However, when the Lion and the Unicorn work in harmony towards the same goal, no other creature can withstand them because they represent a union of opposites.