History of the Trinity Knot The trinity knot is the simplest and most popular of Celtic Knots, symbolizing a triune God. The Celts were very familiar with the idea of the trinity, everything came in threes; The three stages of womanhood: maid, mother, crone, The three elements: earth, fire, water. Christianity embraced this knot to symbolize the Father, Son, and Holy Ghost in many of the early Christian illuminated manuscripts such as The Book of Kells. The trinity knot is a beautiful Celtic design which is associated with eternity and eternal love.