More was a prolific scholar, literary man, critic, and patron of the arts. His writing and scholarship earned him great reputation as a Christian Renaissance humanist in continental Europe, and his friend Erasmus of Rotterdam dedicated to him his masterpiece, In Praise of Folly or Moriae Encomium (the book's title puns More's name; "moria" is folly in Greek). Erasmus described More as a model Man of Letters. The humanistic project embraced by Erasmus and More sought to reexamine and revitalize Christian theology by studying the Bible and the writings of the Church Fathers in light of classical Greek literary and philosophic tradition.
In 1530, things began to go downhill in the relationship between Henry VIII and Thomas. The latter refused to sign a letter by the leading English churchmen and aristocrats asking the Pope to annul Henry's marriage to Catherine. He also quarrelled with Henry over the heresy laws. In 1531 he attempted to resign after being forced to take an oath declaring the king the Supreme Head of the English Church "as far as the law of Christ allows", but he refused to take the oath in the form in which it would renounce all claims of jurisdiction over the Church except the sovereign's. In 1532 he asked the king again to relieve him of his office, claiming that he was ill and suffering from sharp chest pains. This time Henry granted his request.
It wasn't long until a charge of accepting bribes was levelled against Thomas, though the false charges had to be dismissed for lack of any evidence. In early 1534, More was accused of conspiring with the "holy maid of Kent", Elizabeth Barton, a nun who had prophesied against the king's annullment. Again, More side-stepped the charge by producing a letter in which he had instructed Barton not to interfere in matters of state. In April of the same year, More was asked to appear before a commission and swear his allegiance to the parliamentary Act of Succession. He accepted Parliament's right to declare Anne Boleyn the legitimate queen of England, but he steadfastly refused to take the oath because of the anti-papal preface to the Act, asserting that Parliament had the authority to legislate in matters of religion by impugning the Pope's authority, which More simply wouldn't accept. Thomas also refused to swear to uphold Henry's divorce from Catherine. John Fisher, Bishop of Rochester, also refused the oath along with More.
Four days later Thomas More was imprisoned in the Tower of London, where he prepared a devotional, Dialogue of Comfort against Tribulation. While imprisoned in the Tower, he had a few visits from Thomas Cromwell who urged him to take the oath, but More persistently refused to do so.