The promise of continuity and rebirth is a powerful aphrodisiac for a warrior entering battle.  Interlaced key patterns are archetypal symbols of eternal life.  In Celtic artwork the designs reflected their belief in the continuous cycle of life: Birth, Death, Rebirth.  They believed that all the strands of one's many lives were interrelated, with no beginning and no end.  The key pattern reflects the Indo-European origins of the ancient Celts, particularly as the evolved in the Iberian Peninsula