What is the main conflict in A Man for All Seasons by Robert Bolt?

Sir Thomas More is a close friend of King Henry VIII. As a philosopher and thinker, though, he morally objects to Henry divorcing Catherine, his wife. She has not born him a male heir, and Henry is obsessed with creating a progeny. At the time, divorce was not legal as it was controlled by the Roman Catholic Church. More cites that the Pope, head of the Catholic Church, would not likely provide a special dispensation for the divorce. The Pope had already granted Catherine the ability to marry Henry, but only after it was revealed she and her first husband, Henry’s deceased brother, had never consummated their own marriage. More discusses his feelings with the current Chancellor, Cardinal Wolsey, but Wolsey feels More is being impractical.