Christianity seems to have been the first attempt to impose a fairly uniform creed

uniting tribes and other groups, presumably to try to hold the Roman Empire together. Though this view may underestimate other groups' interests, notably what are now called 'Jews', who had their own systems (including the Ghetto and Kahal and 'rabbi' systems). It encouraged conversion, which may have been unique in religions at the time.
      Reviews of the ancient world suggest Jews in Alexandria modified other religions. Their methods were used later in inventing Islam for Arabs.
      These articles question whether Jesus ever existed, whether God dictated the written material, how much was forged, how violent the process of imposition was, how 'blasphemy' and 'heresy' were dealt with, how different western and eastern churches were and are, how Protestantism and newer fundamentalisms developed, how Christianities differed from other religions, and how Christian systems battle other power structures.
      The importance of money as a factor in long-term 'conversions' has historically been vastly under-rated.
      (NB Critics of any system often produce instances of corruption, dishonesty, cruelty, etc, but these things may happen under any system, so a more sophisticated comparison works better. Christianity has been under systematic attack by Jews—at least, that's their projected image, hiding their symbiotic relationships. Jews have similar connections against and with Muslims, in recent centuries, quite apart from rationalist attacks: so it is intelligent to examine 'Judaism' in detail.
      I've used the word 'rationalism' for want of a better word; it has rather irrelevant associations with fractions and numbers.)