Who is a man for all seasons and why, in the play A Man for All Seasons?
Your question is not complete - can you repost it, especially the second part?
To answer the first part, this play is based on Saint Thomas More, Chancellor of England during the reign of Henry VIII. Henry VIII wanted to divorce his first wife, Catherine of Aragon, because she was getting old and had failed to bear him a male heir. Henry wanted to marry Anne Boleyn, but he needed to get a divorce first. At this time, England was Catholic and divorce was not permitted.
Sir Thomas More opposed the Protestant Reformation. Henry VIII eagerly embraced the ideas of the reformers like Martin Luther because he wanted to break the power of the Catholic church in England and because he wanted to be able to obtain a divorce.
More was imprisoned and eventually beheaded by Henry in 1535 because the king grew weary of fighting with him and because he refused to sign the Act of Supremacy which declared the king to be the head of the church of England. If the king was declared the head of the church, the king could do whatever he wanted, including getting a divorce.
Read about the play here on enotes.