Celtic art dates back to prehistoric times. At one time, people identified as Celts and speaking Celtic languages dominated the European continent, even having a significant presence in modern Turkey. These prehistoric Celts left a rich heritage of pottery, ornate weapons and jewelry and other artifacts that have contributed to our knowledge of ancient Celtic art, many of the elements of which remain important to Celtic art to this day.
Irish art inherited many elements from ancient Celtic art, including natural forms involving images of leaves, trees and other vegetation. Irish art, and Celtic art more broadly, both employed a great deal of knots and placed significant importance on geometry and numbers.
Geometry and numbers figure prominently in Irish art and Celtic art in general. An example of geometric figures is the elaborate key and labyrinth designs involving many intricately interconnected lines. Another example is the significant use of spirals to create a circular version of the key and labyrinth designs. The number three also figures prominently in Irish and Celtic art, with many designs making use of triple shapes and three-part figures.
Two commonly recognized elements of Irish and Celtic art are knots and Celtic crosses. The knots involve images of ornate knots woven together in an infinite, complex loop from a single band, or sometimes several bands. The Celtic cross is a typical cross, overlaid with a circle centered on the intersection of the horizontal and vertical lines of the cross. Stone examples can be found throughout Celtic areas, particularly in Ireland.