The Triple Spiral, also known as the spiral of life, found wide usage in the artistic expressions of the ancient Celts. Its representations have been found in abundance at the Bronze Age sites in Ireland.
The ancient Celts believed that life, in all forms, moved consistently in cycles which were ongoing and eternal in nature.
It was also believed that every activity related to life and death happened in three distinct phases, each of which was equally important for maintaining balance of nature.
These three eternal cycles were represented by the triple spiral. So, in short, this symbol stood for all the processes that take place between life and death.