The Demise of Zoroastriansim

The New York Times had an interesting article today on Zoroastrianism, an ancient religion, about 3000 years old, based in Persia that at one time was spread across the eastern Mediterranean. I remember studying about it and being intrigued by it in the Religions of the World course I took in college. It is estimated that at its peak it had 40-50 million adherents. Today the number of Zoroastrians numbers in the tens of thousands, and those who practice this faith are afraid that it might well die out in the next generation. Judaism encountered it especially during the exilic period and it is said to have influenced some of its concepts. For a variety of reasons--persecution, assimilation by other cultures and religions, by a low birth rate of those who practice this faith, to mention a few--have colluded over the centuries to cause its steep decline.

For me it raises the issue of my own faith--what keeps a faith vital and alive. I, of course, would say as a Christian that I believe Christianity is true in a way the Zoroastrianism is not, and this is certainly problematic to a faith's enduring vitality. However, people of other faiths would no doubt say something similar, and the fact that something endures is no guarantee that a belief is true. What do you think is essential for keeping our faith alive and preventing it from becoming some kind of relic?