Does "it" refer back to "the sublimest morality" here?

1) Does "it" refer back to "the sublimest morality" here?
2) Does "which have been invested" refer to "the corruptions have been invested"? If so, what does "invest" mean? Inflict/cause?

Context:

Jefferson advocated a "wall of separation" between church and state not to protect the church from government intrusion, but to preserve the freedom of the people: "I consider the doctrines of Jesus as delivered by himself to contain the outlines of the sublimest morality that has ever been taught;" he observed, "but I hold in the most profound detestation and execration the corruptions of it which have been invested by priestcraft and established by kingcraft, constituting a conspiracy of church and state against the civil and religious liberties of mankind."

More:
http://www.all-creatures.org/murti/art-secularism.html