In the post somewhere below on Jury Duty, the subject of Thomas More and how he approached martyrdom briefly arose. This is a complex issue as there was a widely prevailing opinion at the time that Papal supremcy was an ecclesial law and not of Divine origin. This opinion was bolstered in popularity by the personal immorality of many of the popes in 15th and early 16th century and because of the secular or territorial authority they also wielded. Thomas More was not a theologian and only revised his opinion (to Papal supremacy being Divinely ordained) when he finally researched the topic (possibly he consulted Bishop John Fisher?) when Henry VIII wrote his defense of the Papacy. Recall Thomas More originally warned Henry not to give the Pope so much power - but Thomas More was finally convinced.
However, regarding Thomas More's seemingly tendency for self-preservation instead of embracing martyrdom, Thomas More himself writes on this in his letters from the Tower:
"I have not been a man of such holy living, as I might be bold to offer myself to death, lest God for my presumption might suffer me to fall; therefore I put not myself forward but draw back. Howbeit if God draw me to it Himself, then trust I in His great mercy, that He shall not fail to give me grace and strength." From Bethany, the small holding in Bethune...Oremus pro invicem!
From Bethany, the small holding in Bethune...Oremus pro invicem!