Pietà <span>is the name for a standard subject in Christian art, that of Mary, the mother of Jesus, holding her son after he was taken down from the cross.
This type of art is most often found in sculpture, however, it can sometimes be found in paintings as well. The most famous sculpture portraying this particular event is Michelangelo's </span>Pietà found in St. Peter's Basilica in Vatican.
Based on the excerpt from Joseph Conrad's "The Lagoon", I think that it takes Arsat all night to tell his story. I have inferred such due to the sentence: "<span>Before his face the sun showed its edge above the tree-tops, rising steadily." This means that the sun has already risen. Arsat told a story about his past wherein he and Diamelen, escaped from the rajah's men. </span>