On the second visit to the witches, Macbeth receives a series of prophecies that will be of great significance at the end of the play. The audience, importantly, has already learned that Hecate plans to make a series of apparitions appear that will make Macbeth overconfident. So when Macbeth is confronted by three apparitions, they know that he is choosing to interpret their predictions in an overly-optimistic light. The first apparition, an armored head, says to beware of Macduff. This seals the fate of Macduff's wife and child, who are murdered when Macbeth sends assassins to Macduff's palace. The second is a bloody child (as in a newborn) that tells Macbeth that he cannot be harmed by anyone born of a woman. This, of course, comes to pass when it is revealed that Macduff was born by caeserian section, not a normal birth. But Macbeth doesn't consider this possibility at the time. Third, he is informed by a child holding a tree that "Macbeth shall never vanquished be until Great Birnam Wood to high Dunsinane Hill shall come against him." This comes to pass when the troops assaulting Dunsinane cut boughs from the trees in Birnam Wood as they march on the castle. Finally, the witches conjure a procession of kings, the last of which holds a mirror in which can be seen a reflection of Banquo. In this scene, as in others, Shakespeare cleverly raises questions, without resolving them, about the role of the supernatural and that of human agency.