A Celtic knot, also referred to as the "mystic knot" or the endless knot, is also known as the "Triquetra." Celtic knots are an Irish symbol, and the most notorious artwork in Celtic history, first appearing around 450 AD. The knots can be seen in mosaics on Roman floors as well as in patterns in Islamic, Ethiopian, and Coptic art, as well as in Byzantine architecture, and architecture from all over Europe. There is not much information about the purpose of these Celtic knots, but because of the large repetition of their existence throughout history, we are able to infer some basic information about them.
Some historians believe that the Celts were not allowed to draw any realistic depictions of living creatures back then, so they instead drew these complex and mysterious geometric knots. Some think the knots represent our most primal selves as we think about the infinite cycles of birth and rebirth. In ancient times, Celtic gifts with Celtic knots on them were given to represent good wishes for luck with new endeavors or general longevity.
The Celt's believe in the interconnectedness of life and eternity, and all physical and spiritual things. The knots in the Celtic knot therefore have a sacred geometry with complete loops in them, essentially infinity knots which have no beginning or end, representing the continuing cycle of experience. This infinity design may also represent the timeless nature of mankind's spirit, or the uninterrupted life cycle. These knots come in various shapes from simple to complicated knots.
Superstitious people use the Celctic knot as a charm- protecting themselves against sickness or anything that might interfere with a peaceful, calm existence. Because of this belief, Celctic knots are often found in jewelry, in the home, or on clothing.
While the Celtic knot is normally associated with the Celtic islands, it was also often found in many locations around England, and was then exported to Europe. Celtic knot styles are now found all over the world from Europe to Tibet and Africa. Nowadays, Celtic knots are thought of as a symbol of National identity for Irish, Scottish and Welsh people.
Celtic knots are also found amongst people who believe in new age religions, magic societies, and other groups who want to associate with the oldest traditions of Ireland.