What are the historical origins of the Cross?

"Almost everyone ancient objects were found which were distinctive shapes and crosses various periods dating from much older than the Christian era. India, Syria, Persia and Egypt provides us with countless examples. ... Using the cross as a religious symbol in pre-Christian times and among non-Christian peoples can be considered almost universal in most cases, linked to some form of nature worship. "- Encyclopædia Britannica (1946), vol VI, p 753. "The shape [of the cross with two arms] has its origins in ancient Chaldea. In this country and in neighboring countries, including Egypt, the cross was used as a symbol of the god Tammuz [the shape of the mystic Tau, the initial of his name]. The mid third century AD, churches or departed from some teachings of the Christian faith or falsified them. To increase the prestige of the apostate ecclesiastical system, pagans were received into the church without being regenerated by faith and were allowed to remain, largely pagan signs and symbols. Thus, Tau or T, the most common form left below the crossbar, was adopted as a symbol of the cross of Christ