The Egyptian cross or 'ankh'
Note: in modern Biology this is the symbol of a female, because of the fertility that it represents in Ancient Egypt.
The Celtic cross:
The symbol for a cultural blend of medieval Catholicism and ancient Celtic traditions. The Celtic cross also represents the neo-pagan followers of the French anti-Christian philosopher Alain de Benoist.
Even clear on the other side of the globe, when the Roman Catholic missionaries arrived in Mexico large stone crosses were already erected, probably to the "god of rain."
These are but a few. Virtually all pagan societies have some pre-Christian variation of the cross.
The cross, or crucifix is thought to have originated with the Roman Emperor Constantine The Great.
The legend goes that in the year 312A.D. BEFORE a great battle Constantine saw a vision in the sky of a flaming cross superimposed on the sun, and he heard in this sign you will conquer. He therefore had the symbol painted on the shields of all his solders. After winning the battle Constantine is said 2 have converted to Christianity and made it an accepted religion (not the official religion) in the Roman Empire.
The Babylonian cross was the recognized symbol of Tammuz in both Chaldea (Babylon) and Egypt.
Emperor Constantine receives the major share of historical credit in uniting the sun worshiper's of the empire with the Christian’s of the Empire.
After the reformation Protestant's didn't admire the cross as the symbol of Jesus. Especially the 16th & 17th century Puritans. However in 19th, 20th, 21st century the cross has been ever increasingly accepted.
LET IT BE KNOWN: In ancient Babylon crosses were used as symbols of the sun-god. The emperor Constantine (the 1st roman emperor to convert 2 Christianity and end Christian persecution) was a sun worshiper. Now the question begs to be asked did this pagan Roman emperor really get converted because he saw a vision from the true & living God? If he saw any vision at all it was of the sun-god for he saw the sun-god's symbol in the sky.
To read more check out "The Two Babylon's" (Chapter 5, section 6)by Alexander Hislop or click the link
There are many more variations to the cross and its pre-Christian usage. There are quite a few at: