The Gospel was smothered by the incorporation of syncretic pagan beliefs and practices and rituals. You will have to dig back almost 1800 or so years to get to the beginning. Even in the time of the Apostles, they warned about those who would sneak in and try to supplant the simplicity of the Gospel with heresy. At the end of his life, the Apostle John notes in Revelation, that several churches had already had their lampstand removed.
How so? And what weird Gospel are you adhering to?