The origins of the first cross image are still unknown today. What is known is that the cross has been used by many ancient cultures. In fact, crosses were used way before Christianity became a formal religion.
Various cultures such as the Babylonians, Assyrians and Egyptians used crosses to represent gods or mythology. In Babylon, the cross symbolizes the moon god, while the Egyptian cross (Ankh), represented life and the "knot of Isis".
Various pagan religions used the symbol of the cross to represent various aspects of life including deities.
During the times of Christ, the cross symbolized crucifixion. This is where the symbol of Christianity is derived.
As designs for tattoos, crosses are one of the most popular, if not the most popular. There are various designs in crosses ranging from the simple to very ornate.