All of the current, major western religions, which are considered to be monotheistic, trace themselves back to the mythological patriarch Abraham. There is more of similarity in these Abrahamic religions than differences, but sadly the latter become the focus of the intolerant members of each. All three can be said to have overlapping roots of origin, though Judaism is an ancestor of both Christianity and Islam. Major so-called religions of the East, such as Buddhism and Confucianism, are often treated more as ethical systems or philosophies of life than religions that are additionally besotted with details of the principal God, prophets, and their lives.
In our country, we have been generally favored by arriving on the stage of history in relatively recent times and in having "founding fathers" attuned to secularism. Their bent on Christianity was often ill-disguised skepticism. For example, Thomas Jefferson , writing to his predecessor, John Adams, stated "The day will come when the mystical generation of Jesus, by the Supreme Being as his father, in the womb of a virgin, will be classed with the fable of the generation of Minerva in the brain of Jupiter." Jefferson, a rather learned man for his time, was aware of the difference between possibilities and probabilities and also recognized there was a linkage between "modern" religions and those past.
More recently, Tom Flynn, the Editor of Free Inquiry, collected articles documenting contradictions in the well-loved Christmas story for the 2004 issue of that highly regarded magazine. Richard Dawkins, in his book The God Delusion, points out that among these articles, one by Robert Gilloily shows how all the essential features of the Jesus legend, including the star in the east, the virgin birth, the veneration of the baby by kings, the miracles, the execution, the resurrection and the ascension are borrowed -- every last one of them -- from other religions already in existence in the Mediterranean and Near East region.
It would seem appropriate, then, to trace back to some of the bases of the beliefs which are held by believers of today. Most of the pieces of our modern, western religion are known to derive from those in early Egyptian and Mesopotamian kingdoms. It is instructive to begin about 3,000 BC (or BCE) with ancient Egypt, the oldest of these in terms of a written language that details much of what today is expressed as heaven, hell, rebirth after death, the story of Moses, virgin with child, and many aspects of the Abrahamic creeds, especially Christianity. Around 2,500 BC, the input of civilizations that stem first from Sumer then from Babylon and later Assyria additionally contribute to our modern beliefs.