While the Celtic Cross is certainly a Christian symbol, it has its roots in ancient pagan beliefs at the same time. The Celtic cross is a form of Christian cross featuring a nimbus or ring that emerged in Ireland in the Early Middle Ages. Some say the circle stands for the Roman sun-god Invictus, thus giving the name of Celtic Sun Cross. Others say it represents the halo of Jesus Christ. Others simply see it as a holdover from its pagan roots as a sun symbol.