What did Thomas More refuse to do?

Thomas More refused to acknowledge King Henry VIII as the Supreme Head of the Church of England, thereby rejecting the king's authority over religious matters. More's refusal was rooted in his devout Catholic faith and his belief in the Pope's supremacy. As a result of his stance, he was imprisoned and ultimately executed for treason in 1535. His steadfastness made him a martyr and a saint in the Catholic Church.