A very interesting symbol is the Celtic Cross. Dating back to about the 5th Century AD, these large carved crosses with a circle at the point of intersection were highly decorated with spirals, curves, and geometric patterns. Known as a High Cross, the oldest Crosses were formed from large, flat rock forms in the earth.
In later versions, these Crosses were stood upright ranging from the smallest at about five feet to some sixteen feet or higher. It was believed that the ringed portion of the Cross was added to support the weight of the head and arms of the structure and later included for decorative purposes.
Other historians will point out that the Celtic Cross was also known as a Sun Cross or Sun Wheel and was a symbol of Odin, the Norse god. Many believe that the early Christians used the symbol of the sun imposed on a cross as an attempt to convert the Celtic population away from pagan beliefs to Christianity. In Irish legends, it is believed that St. Patrick was the first to initiate the first Celtic Cross by sketching a circle over a Latin Cross.