Time and Loss
These four closely connected themes overshadow everything that happens in 2 Henry IV. The father figures of 1 Henry IV (Northumberland, King Henry, Falstaff) were vital and strong men. Now, Shakespeare depicts them as nearing the end of their days. They feel their age; they spend a good deal of time talking about the dead. Descriptions of physical ailments abound.
The theme of loss is about more than human life; loss of old friends is another shadow over this play. Though Falstaff still believes himself to be Hal's friend, they rarely interact. The time is past for Hal and Falstaff; Hal's throne demands it, and Henry V will betray the man who has been his surrogate father and friend.
Atonement
This theme applies to Henry IV's usurpation of the throne and murder of Richard II. It also applies to Hal's attitude toward his reign.
Henry IV's longstanding dream has been a Crusade to the Holy Land, which would help him atone for the murder of Richard II. But civil strife makes the Crusade impossible; Henry IV spends all of his time putting down insurrections. Atonement becomes impossible during his lifetime. It will be up to Hal to carry out the campaigns abroad.
For Hal, who has spent his youth roaming around with rogues, thieves, and prostitutes, atonement will be part of his reign. He has planned all along to become a responsible king. At his father's deathbed, he promises that his reign will be great. After he is crowned, he promises those assembled that his actions as king will atone for his past.
Expectation
Expectation is an integral element of a history play, in which the audience, even on opening night, always knows how the play will end. Shakespeare was not the first to deal with this problem: all Greek tragedies dramatized myths that were familiar to the audience. The playwright must find new ways to surprise the audience, or he must find ways to make the expected ending part of the satisfaction of the work. One of the ways to do this is prophecy. Prophecies riddle the history plays, and part of the satisfaction they provide comes from dramatic irony. That is to say, usually the audience understands the meaning of a prophecy long before the characters do. But Shakespeare also makes use of false prophecies (think of the prophecies predicting Henry IV's defeat in 1 Henry IV). Shakespeare often plays with expectation so that the limitations of historical truth do not translate into a boring theatrical experience.
Expectation also makes us see the past as part of a pattern. Expectation and fulfillment put events into a larger context; though the characters onstage do not know it, their actions lead to the world as we know it today. A sense of destiny pervades Hal's character. He will become a great English king, and the audience knows it long before the characters of the play do.
Burden of Leadership
The men who wear the crown in the Henry IV plays speak of kingship as destiny. Henry IV is seen in this play as sleepless, anxious, fearful for the future. His duties as monarch and anxieties about the stability of his dynasty are sources of pain, not pleasure. Hal also speaks of the crown as a burden. The duties of kingship come first, supplanting friendship. Likewise, Hal's crown will necessitate the betrayal of Falstaff and the Eastcheap crowd.
Fathers and Sons
Filial relationships are an important theme in both 1 Henry IV and 2 Henry IV. In this play, the theme becomes inextricable from the themes of aging, loss, and death. The fathers in this play are more vulnerable, feeling their age and their mortality. For Hal, there are two father figures: Henry IV, the father whom he has continually disappointed and defied, and Falstaff, who has been his surrogate father. Hal must take care of business with both of them. With his father the king, he must make amends. The atonement will come after his father's death. But for Falstaff, there will be betrayal.
Maturation and Sacrifice
It has been argued that the plays of the second tetralogy (Richard II, 1 Henry IV, 2 Henry IV, and Henry V) are Shakespeare's version of a dramatic epic, featuring Prince Hal as the epic hero. Henry IV, Part Two is chief among these as the play in which Hal truly transitions out of his youthful antics and into a responsible and respected king (Henry V). However, the transition is not an easy one, and the play balances Hal's maturation with the cruel and difficult rejection of the companions with whom he spent his younger years. The play suggests that in order to become a strong and effective king, one must sacrifice certain pleasures, indulgences, interests, and even friends.
Warfare
Both 1 Henry IV and 2 Henry IV are interested in the nature of war. In 1 Henry IV, audiences were introduced to the senseless violence, cruelty, and destruction that war brings with it (mostly through the figure of Falstaff, who speaks crudely but honestly about what will happen to the soldiers on the battlefield). This play, notably, does not contain any battle scenes like its predecessor, but it is still interested in interrogating the utility – or futility – of warfare. Throughout the play, a number of characters are seen engaging in corrupt and ignoble wartime practices, including Falstaff and Lancaster. Furthermore, on his deathbed, Henry IV tells Hal that the best way to distract his own people from potential rebellion is to wage war with other nations, thereby sacrificing the lives of foreigners for stability at home. These instances provide audiences with a distinctly unsavory portrait of war as weapon wielded by those in power at the expense of the common man.
