Explain: "Long live the king! The king is dead!"

The literal meaning of the above line is that the king has died, and it is hoped that the new king will live a long time. However, the poet through this expression tries to bring out the irony of this slogan shouted by the ministers and the crowd, where they are praising the king for his wisdom that has resulted in his hanging. It is highly ironical that they are hoping that he lives long through those principles of his, which have inadvertently caused his death.