The triquetra holds a special place in many different cultures and contains a unique significance for each of them. When we ask, “What do the triquetra represent?” there is no one answers that is entirely correct or suitably comprehensive. In short, the triquetra is one of those symbols that ‘mean many things to many people.’ 
The meaning of Triquetra or the Celtic Trinity Knot Symbol
It is not alone in that respect. It seems that the older that a symbol is, the more diverse a range of peoples there exists who have adopted it to their own cultures and traditions. One might even say that a widespread prevalence of a particular symbol, like the triquetra, is almost directly linked not just to its popularity but its age. Sometimes, the beliefs of different cultures sharing the same symbol may overlap significantly. In such cases, it is easy to trace the story of that symbol’s journey. In other instances, the true tale of the evolution of the use of a symbol is less obvious, and all memory of how it came to be adopted has long faded from our collective knowledge.
Elements of the Triquetra or the Trinity Knot
‘Triquetra’ is a name of Latin origin and comes from the Latin word ‘Triquetrus,’ meaning ‘three-cornered’ or ‘triangular,,’ and it is clear how this symbol gained that name.
The popular term for it today is the Trinity Knot and the Irish Love Knot.
Of course, this is the name by which we have come to know it, but it does not point to its origins. It is because the triquetra, despite being of pagan origin, were embraced by the Church at a time when all their writings and rituals were conducted in Latin.
While the shape lent itself to its name, there is a deeper meaning behind the three-sided way that many people miss. Each of the three leaf-like shapes that form the symbol is not arbitrarily drawn; they are a mathematical shape called vesicae piscis.
A vesicae piscis is the shaped defined by the overlap of two circles of equal size when each is positioned so that its center is on the other’s circumference. In ancient times, it was a symbol of the feminine because it looked like the aperture of birth.
In essence, the shape is a stylistic rendition of a fish. The Church took the name vesicae piscis, which is translated as ‘bladder of the fish’ because Christ is described as a ‘fisher of men.’
The repetition of the trifold of the vesicae piscis referred to three births, which is an idea that predates Christ.
The beauty of the triquetra is that what appears to be a rather complicated shape is comprised of just three simple lines. It uses three vesicae piscis by the use of three arcs; each blend into one end of its two neighbors to complete a path without end.
Sometimes, the triquetra design is also shown with a circle interlocking the triangular form. That is also another condition that holds special attention later in this design.
The very earliest examples of the triquetra are Indian and date back five thousand years.
There is little doubt among scholars that several religious practices, as well as portions of language and alphabet shared between the people of Europe and India, are evidence of a shared origin that branched off many thousands of years ago.
It may be that the early Indo-Europeans, commonly called the Aryans, are the link between ancient India and the triquetra we know to be an old European symbol today.
Nowadays, the triquetra is most commonly recognized as a symbol with its origins in Celtic tradition, with evidence that shows that the Norse Viking people also used it at about the same time, and that is 7th and 8th century A.D.
The triple aspect of the triquetra is what made it a very versatile symbol. Many cultures put their interpretation on its meaning(s), and we see a recurrence of the number ‘3’ and its association with the triquetra everywhere it was used.
The Pagan Celtic Triquetra Symbol
For the pagans who revered nature and saw the hands of their gods in all things, the Three could be God, Goddess, and Man, or it could represent the three realms, Heaven, Hell, and Earth. Others could have seen it as the world around us in sky, land, and sea, or, as is popular in Wiccan circles today, they could have interpreted the triquetra as the three aspects of the female: Mother, Maiden, and Crone.
The last of those is very telling because the vesicae piscis of the shape alluded to the female reproductive opening.
That shape was their connection to the miracle of Life, both during the act of creating Life upon the union of man and woman, and the welcoming of Life into the world upon birth.
The triple nature of the feminine Divine is a popular theme in ancient pagan lore. The tripartite representation is probably most famous as the Triple Goddess. This symbol shows a full moon in the center with a waxing moon on one side and a waning moon on the other.
The moon itself was a firm reference to the female because their menstrual cycles could be timed by it. The mensuration process has also linked the process of bringing Life into this earth, completing the circle.
Thus, for the ancient Celts who populated the northern European regions before the rise of Christianity, the triquetra was very closely associated with nature and Life. The interpretations strongly hint at it being more closely associated with the female than the male.
Triquetras dating to the pagan age of the Celts has been found inscribed on rocks.
The Christian Celtic Triquetra
However, when we talk about the relationship between the Celts and the triquetra today, the most common examples do almost entirely away with the pagan traditions and talk of the Book of Kells instead.
Most do not realize that the Book of Kells, which is an ‘illuminated manuscript’ (decorated with gold, silver, and colorful dyes) from the Christian Celtic era.
It contains Latin interpretations of the four gospels of the New Testament and has been dated to 800 A.D. (In a nice coincidence, this book is today in Dublin at Trinity College).
In a time when Christianity was spreading into the northernmost parts of Europe, it was continually encountering the erstwhile prevalent pagan religions that had flourished there.
The adoption of the familiar triquetra symbol that the pagans used was the ideal way for the new religion to establish a foothold without being too disruptive and thus to deflect undue criticism and hostility.
In the Celtic Christian world, the tri-symmetrical shape was quickly interpreted as alluding to the Holy Trinity of the Father, the Son, and the Holy Spirit. It can be said that the triquetra evolved from being a symbol that hinted at the female (mother, maiden, crone) to one that would be interpreted as male (‘Father’ and ‘Son’).
However, despite the prominence that the Trinity holds in the Church, we see that the early Christian Celts did not often depict the triquetra on its own in the early days of its use in their culture.
The Book of Kells, one of the most magnificently-decorated works of the Insular Art (Island Art) period, features the triquetra but never as the subject of discussion or an illustration; is it always used in the margins and other spaces as filler’.
