Hitherto Bonner had had a reputation as a somewhat coarse and unscrupulous tool of Cromwell – a sort of ecclesiastical Wriothesley, he is not known to have protested against any of the changes effected by his masters; he professed to be no theologian, and was in the habit, when asked technical questions, to refer his interrogators to the theologians. He had graduated in law, and not in theology. There was nothing in the Reformation to appeal to him, except the repudiation of papal control; and he was one of those numerous Englishmen whose views were faithfully reflected in Henry's Act of the Six Articles. Indeed, almost his first duty as Bishop of London was to try heretics under these articles; accusations of excessive cruelty and bias against the accused were spread broadcast by his enemies, and from the first he seems to have been unpopular in London. He became a staunch conservative. During the years 1542-43 he was again abroad in Spain and Germany as ambassador to the emperor, at the end of which time he returned to London.