Hrm? Substance dualism is important. The spirit is not the body, and neither is the body the spirit. You are right that the spirtual world does affect the body as does the inverse, but we have to be careful not to say that they are exactly the same. Imran - God's kingdom is not going to be brought about by Christians here on Earth, but rather by Christ himself upon his return. Our purpose is to spread the Gospel and the truth of Christ, not to bring about the universal kingdom.
It was the exact same pope that issued the bulls you referred to. You claimed, (entirely falsely), that the Bulls you cited advanced slavery, while (as usual), ignoring the crucial evidence.