The triquetra has been found on runestones in Northern Europe and on early Germanic coins. It presumably had pagan religious meaning and it bears a resemblance to the Valknut, a symbol associated with Odin. The triquetra is often found in Insular art, most notably metal work and in illuminated manuscripts like the Book of Kells. It is also found in similar artwork on Celtic crosses and slabs from the early Christian period.
Christian Symbolism: The Triquetra represents the Holy Trinity: the Father, Son, and Holy Spirit. The unbroken circle represents eternity. The interwoven nature of the symbol denotes the indivisibility and equality of the Holy Trinity. It symbolizes that the Holy Trinity is three beings of power, honor, and glory but is indivisibly one God