
Celtic knotwork was a decorative and a religious art, borne from the traditions of the ancient Celtic people who settled in Britain during the 7th Century B.C. Celtic art had three main functions:
Knotwork developed from plaitwork, a pattern of straight diagonal lines joined together with curves. Plaitwork and knotwork designs have been used extensively in Roman, Greek, and Egyptian art throughout history.
In the 6th Century A.D., there was extensive use of plaitwork to decorate altar screens and covers for church vessels in Italian churches. Broken lines, which enabled interweaving grew in popularity as the Celts used their knotwork to decorate irregular spaces on stone crosses, manuscripts, jewelry, and wood. Angular lines and pointed loops were added to fill in the corners.
The never-ending path of the knotwork strand represents the permanence and the continuum of life, love, and faith. To the ancient Celts, interlacing knotwork in one continuous line symbolized eternity.
The best example of Celtic knotwork is seen in the Book of Kells at Trinity College in Dublin, Ireland.