The divergence in the views between Thomas More and Thomas Cromwell is emphasised through their different beliefs and opinions towards Henry's divorce of Katherine of Aragon and his marriage of Anne Boleyn. Thomas More, early on in the novel, clearly declares himself to be a Catholic who believes in papal supremacy and rejects the teachings of Luther. Thus is it that when Henry creates the Church of England and jettisons Catholicism he finds himself in an extremely exposed position, having already made a very clear stand against the same Protestantism that his king has now embraced. Note how the situation intensifies when it is required that he swears fealty to his king and the new power he has assumed:
More is now required to swear to the Act of Supremacy, an act which draws together all the powers and dignities assumed by the king in the last two years. It doesn't, as some say, make the king head of the church. It states that he is head of the church, and always has been.
More's refusal to swear to the Act of the Supremacy is what leads to his death, as although he has nothing against Henry being King, he cannot accept what Henry has done in abandoning the Catholic church and embracing Protestantism in order for him to divorce and marry Anne Boleyn. This is of course in stark contrast to Thomas Cromwell, who helped Henry engineer this rejection of Catholicism in order to get him the woman he wants to marry. Cromwell's beliefs are defined by pragmatism, whereas More's beliefs are defined by loyalty to his concept of religion and faith, and this is what leads More to an early grave.