The King James Bible is called that because King James VI of England paid to have the Bible translated from Latin into English for the Church of England, not the Catholic Church. The Church of England split off from the Catholic Church about a hundred years earlier during the reign of Henry VIII because the Catholic Church would not grant him a divorce from his wife.

The doctrine of separation of church and state was adopted by the authors of the Constitution to ensure that there would be no establishment of a state religion like in Great Britain where the Church of England is the official state religion.

Remember, always read up on your history before commenting.