A product of our times?

Being as faithfully religious as I am, the question of the legitimacy of other faiths has occurred to me quite frequently. In fact, Alexa and I often discuss the ecumenical nature of faith, and the exact reason why I find Catholicism to be validated against this principle (Vatican II).
However, I would be remiss if I pondered these questions without asking the question: Are my beliefs truly as valid as I think that they are, or am I merely a product of Christianity's two thousand years of history and theology?
As it stands, that question is a very legitimate question, seeing as Christianity does only have two thousand years behind it and religion in general has been traced back at least five thousand years (and by the Old Testament standards, six thousand). If my beliefs about God become man only go back to the early Christians and theologians such as Athanasius, Origen, Jerome, Augustine and others, then what am I to say about those who lived before?
Not only that, but some of the most popular religions in the world predate Christianity by quite a long time. Buddhism has five hundred years on Christianity, while Hinduism has at least six hundred. Judaism can be traced at least another thousand years before Christ. Where does that leave those people? If we might state that the proof of Christianity's validity is in its longevity than what do we say about these faiths? Or what about Islam which is only six hundred years younger than Christianity?
Questions such as these give some people a reason to doubt their faith. Others claim that God did simply not reveal himself to these people. Some see other faiths as stumbling blocks and scandals in the way of Christianity (specifically those who read the Apocalypse of John literally).
However, I find my faith validated in various other places. As a bit of a Classics scholar, the Romans and Greeks fascinate me. Of course both of these nations worshiped a plethora of gods, and neither one of their religions have survived the test of time. But what seems peculiar to me is not their faith, but those who were not of their faiths.
One of my favorite philosophers of all time, Socrates, was accused of being an atheist. However, peculiarly, in nearly every dialogue I've ever read of his, he mentions deity, or Providence or some kind of reference to a God. Furthermore, in his Apology, Socrates talks at length about the spirit that always spoke to him. From a Christian perspective, a lot of Socrates' philosophy seems to mirror Christian thought (which is not surprising considering many of the Christian theologians and philosophers were trained in the Greek style). So I find some encouragement in Socrates' Christian-like thinking.
Furthermore, it seems to me that faiths such as Hinduism, Buddhism, Judaism and Islam started more or less as national faiths. Hinduism, Islam and Judaism all filled in religious vacuums in the cultures where they started. Buddhism came around in a Hindu setting, but it migrated East to more accepting climes. Christianity blossomed in the Jewish region of the Roman Empire. Christianity had to fight against two strong religions, and yet still grew, even when it became outlawed in the empire, and Christians were killed for sport.
So it is that I have faith in the Christian faith. By this I mean not only that I have faith in the guiding principles of Christianity and in the Divinity of Christ Jesus, but also in the faith itself. I believe that Christians can relearn to love. I believe that Christians can relearn to accept others who are different and reach out to those marginalized by society. I believe that Christians can help the poor, protest war, and stand as real witnesses of the love that God gave us. We preach Christ crucified. A doctrine whereby we profess that God's mercy and love were so great that he forgave us all our follies. As Christians and followers of this God, it is our duty to show that Christianity's strength lies not in the power of its followers, but in their love.