The Solar cross is probably the oldest religious symbol in the world, appearing in Asian, American, European, and Indian religious art from the dawn of history. Composed of a equal armed cross within a circle, it represents the solar calendar- the movements of the sun, marked by the solstices. Sometimes the equinoxes are marked as well, giving an eight armed wheel. The swastika is also a form of Solar cross.
The sun cross in its most simplified form (shown above) is known in Northern Europe as Odin’s cross, after the Chief God of the Norse pantheon. It is often used as an emblem by Asatruar, followers of the Norse religion. The word “cross” itself comes from the Old Norse word for this symbol: kros.
The Celtic cross is a symbol of the Celtic Christian Church, borrowed from the pre-Christian Celtic Pagan emblem of the sun God Taranis:
The Celtic Taranis with his wheel
Celtic solar cross
The Etruscan God Ixion was often depicted crucified on a solar wheel (note the similarity to the Chi-Ro cross):
A similar symbol is the emblem of the ancient Assyrian God Shamash:
The Lauburu (four heads), a traditional Basque emblem, is also a form of solar cross:
The lauburu’s origin is unclear, although it is undeniably a solar emblem. In recent times, it most often used as a charm for good luck and protection, and an emblem of Basque pride. The Aztec solar deity Quetzalcoatl, depicted crucified on an equal armed cross: