The triskele is an ancient symbol dating as far back as the Stone Age, making it older than Stonehenge. Oddly enough, it was found in many early cultures in many places around the world. For example, not only was it used to decorate the shields of Greek warriors, it was also carved in stone at the prehistoric Newgrange tomb in Ireland.
Originally from the Greek word "Triskeles", meaning "three legs", the triskele - or sometimes triskelion - is said to represent motion. Indeed, the three legs do seem to visually rotate about its center. In this way, the triskele is a symbol of movement, progress, cycles and action, thereby suggesting that we as human beings should always be growing and becoming better.
Because of its three legs it has come to embody such integral triple relationship such as life-death-rebirth, past-present-future, or mother-father-child.