It belongs to a kind of crosses with a nimbus. In the Celtic Christian world it was combined with the Christian cross and this design was often used for high crosses – a free-standing cross made of stone and often richly decorated. With the Celtic Revival the shape, usually decorated with interlace and other motifs from Insular art, became popular for funerary monuments and other uses, and has remained so, spreading well beyond Ireland.

In Ireland, it is a popular legend that the Celtic Christian cross was introduced by Saint Patrick or possibly Saint Declan during his time converting the pagan Irish, though there are no examples from this early period. It has often been claimed that Patrick combined the symbol of Christianity with the sun cross, to give pagan followers an idea of the importance of the cross by linking it with the idea of the life-giving properties of the sun. Other interpretations claim that placing the cross on top of the circle represents Christ's supremacy over the pagan sun.