John Henry Newman began researching and writing An Essay on the Development of Christian Doctrine while he was still an Anglican. He was a prominent Anglican priest who taught at the University of Oxford. He was hoping to show how the Anglican Church was a middle way between the various Protestant traditions on the one hand and the Catholic Church on the other hand. As he had studied the history of Christian doctrine, particularly during the earliest centuries leading up to the First Council of Nicaea (325) and afterward, he began to be convinced of the correctness of the Catholic Church. The argument that unfolded as he completed his Essay was that a study of the history of the development of Christian doctrine shows how consistently it has evolved over nearly two millennia within Catholic Christianity. All other forms of Christianity, according to Newman’s research, have deviated in some way from the naturally developing doctrine that has evolved following specific rules. This argument was so persuasive for him that by the end, Newman himself converted to Catholicism, becoming the highest- profile Catholic convert of his generation.